We'll have EVERYTHING covered for you right here over the next few hours.
5.56amWell that's that for day one from Flushing Meadows. There has already been plenty of drama, grit, blood, sweat and determination on show, as well as some flashes of class from Andy Murray and Roger Federer. Novak Djokovic begins his defence tomorrow - so join us from 4pm!
5.54amAnd there it is! Devvarman saved two break points but couldn't stop Hidalgo profiting from the third. The Spaniard is through.
5.51amIt's now Hidalgo who is threatening at 0-30. Neither man seems to want to hold onto his serve.
5.44amThe Spaniard has broken through and will now serve for the match.
5.41amSo day one at Flushing Meadows comes down to Ruben Ramirez Hidalgo and Somdev Devvarman.
5.39amCilic seals victory with an ace. Job done. Scare over.
5.38amDevvarman has broken back against Ramirez Hidalgo. The Indian is looking to end a run of three first-round exits in recent tournaments.
5.32amCilic consolidates the break of serve by holding to love. One more game and he has suceessfully completed his comeback from two sets down.
5.31amSince reaching the final in Florida, the Australian has pretty much lost any time that he has come up against quality opposition. Although, he does have one more high profile scalp to his name - that of Richard Gasquet at Eastbourne.
5.29amCilic breaks to go 4-3 in front. He is closing in on victory now.
5.29amMatosevic made the final in Delray Beach, Florida this year - beating Ivo Karlovic, Alex Bogomolov Jr, Ernests Gulbis and Dudi Sela along the way. He eventually lost to Kevin Anderson.
5.25amRamirez Hidalgo is a break up in the fourth set against Devvarman.
5.24amCilic has won both of his five-setters in this calendar year - against Sam Querrey at Wimbledon and against David Nalbandian in the David Cup - an ominous sign for Matosevic.
4.52amSomdev Devvarman trails Ruben Ramirez Hidalgo by two sets, but is a break up in the third.
4.50amThe referee has given Russell a warning because he has not got up out of his seat in time for the restart. He ties his laces 50 times, blows his nose and picks up his racquet almost in slow motion.
4.48amOn replay, simon nearly touched the net while... well, I wouldn't call it a celebration... but you get what I'm saying. He was a bit lucky.
4.48amExtraordinary tennis! Simon looked beaten, then so did Russell, before Simon eventually gets the double break.
3.18amBrilliant tennis all round! Firstly, Federer hits an awesome forehand down the line, which Young magnificently gets up from the volley. Federer then storms into the net, but cannot pass Young, who clips the ball into the empty court.
1.26amRobson had some trouble serving out the set, but she has managed it! Great start!
1.18amRobson breaks again! She is now serving for the first set!
1.17amBut before we leave Armstrong, let me tell you that Fish has broken Soeda's serve and leads 2-0 in the third set.
1.16amApologies - it is level between Simon and Russell. Simon is on serve. We will switch focus to that match, all the while keeping you posted with the latest from Robson's match against Crawford.
1.15amSimon is now a break up against Russell amid a partizan atmosphere on Grandstand.
1.13amLaura Robson has dropped her serve to Samantha Crawford on court four. It's 4-3, with the American on serve.
1.11amMatthew Ebden has beaten Tatsuma Ito in straight sets 7-6 6-3 6-2.
1.05amRobson has broken Crawford. She leads 4-2 in the first set. Fish has ensured that it isn't all doom and gloom for the Americans by winning the second set.
1.03amQuickly! Back to Fish! He looks on course for a two-set lead. It's 5-2 to the American in the tie break.
1.02amMathieu has come through a tough opponent in Andreev, and he did it the hard way by fighting back from two sets down.
1.00amGame, set and match Mathieu. He wins 2-6 4-6 7-6 7-6 6-1.
12.58amThe second set between Fish and Soeda has gone to a tie-break.
12.58amA big backhand down the line sees Mathieu break! He serves for the match...
12.57amMathieu has dragged it back to deuce from 0-40 down. He has broken the Russian, who led by two sets. Mathieu has won both of his sets on tie break.
12.56amAndreev is coasting through this service game. It looks as though Mathieu would just like to serve this one out.
12.55amWickmayer eventually took the first set against Glushko by breaking in the final game for a 7-5 triumph. Simon has broken back against Russell, while it is still on serve in Laura Robson's match.
12.52amLet me switch the main attention to Mathieu's match against Andreev. The Frenchman leads 4-1 in the fifth set. Andreev is on serve. Game on!
12.49amSome terrific hitting from Soeda. 5-5 in the second set with Fish on serve.
12.47amMichael Russell has broken Gilles Simon at the first time of asking on Grandstand.
12.46amIt's looking like a walk in the park for Verdasco. He has taken the second set 6-2 and is now one set away from the next round.
12.45amSoeda has broken Fish as her served for the set and once again we are back on serve.
12.44amLaura Robson's clash with Samantha Crawford on court four. We'll keep you posted on that one.
12.42amChardy has advanced in straight sets 6-3 6-4 6-3 against Volandri.
12.40amGlushko has dragged herself back to parity against Wickmayer. It's 5-5 in that one.
12.39amMichael Russel and Gilles Simon is underway and the American has held serve in the first game.
12.38amMathieu is not hanging about! He has broken Andreev and leads 2-0 in the decider!
12.37amFish holds to consolidate the break. He is now one game away from a two-set lead.
12.34amSoeda has very quickly relinquished his serve and fish now leads 4-2.
12.30amMathieu has taken the fourth set against Andreev. It's going to the wire on court 13.
12.29amA great return of serve from Soeda and we're back on serve in the second set!
12.28amSo that brings you pretty much up to date with all you need to know from New York. Meanwhile, Mardy Fish is struggling with his serve. Soeda has just missed a gimme at the net to break back. We're at deuce.
12.27pmIn the only women's match that is currently in progress, Yanina Wickmayer leads Julia Glushko 4-2 in the first set.
12.25amFernando Verdasco has blitzed the first set 6-2 against Rui Machado of Portugal. Australia's Matthew Ebden is also two sets up against Tatsuma Ito.
12.23amMathieu is involved in another slug fest, this time with Andreev. They are in a tie breaker in the fourth, with the Russian 2-1 up in sets.
12.22amBjorn Phau is a set up against Maxime Athom of Belgium. Jeremy chardy is one set away from sending Filippo Volandri packing.
12.18pmAlbert Ramos is two sets and a break up in the fourth against Robby Ginepri. The American looks like he might be making an early exit...
12.15amKvitova has raced through the second set, taking it 6-1 to advance to the next round. She had struggled to break Hercog in the first, but has no such problems in the second.
12.14amLet me round up some of the action and results for you - very quickly, mind...
12.12amA long rally results in Soeda dumping it into the net. An early break of serve for Fish!
12.11amFish has a break point at 40-30 early in the second set...
12.10amThe rain delay has played havoc with the schedule at Flushing Meadows. Pfft... only at the US Open, right?!
12.09amFish took the first set against Soeda on a tie break 7-3. It was tough work for the American, however...
12.07amGood evening Sports Mole readers. I'm sure that you will join me in thanking Messrs Power and Apicella for their sterling work throughout the day session.
12.04amRight its time for me to bid you goodnight. Tennis insomniacs be sure to stick with Michael Penkman as he guides you through an exciting night of action including Federer, Clijsters and our very own Laura Robson.
12.00amSoeda is proving a tough nut to crack for the experienced American, Fish narrowly edging it 4-2 at the change of ends.
11.55pmFish quickly produced a perfect service game and its tie-break time in the first set.
11.53pmMardy Fish's is now serving to stay alive in the first set on Louis Armstrong, Soeda mounting a comeback to lead 6-5.
11.52pmOver on the Grandstand Court women's fifth seed Petra Kvitova is being pushed all the way by Polona Hercog. The Slovenian forced the first set into a tie-break, which Kvitova claimed narrowly 8-6.
11.50pmElsewhere Russian veteran Nikolay Davidenko booked his place in the second round with a win over Guido Pella in four sets.
11.48pmUS interest is currently focused on the Louis Armstrong Stadium, with Mardy Fish up against Japan's Go Soeda. The 30-year-old currently leads by five games to four in the first set.
11.46pmThere is British interest later on Court 4 as Laura Robson takes on American qualifier Samantha Crawford, with the winner set to face Clijsters in round two.
11.45pmFederer also goes up against US opposition as he takes on the talented but inconsistent Donald Young.
11.44pmClijsters has promised that the US Open will be her last tournament and has pledged to retire on its conclusion. Emotions will run high as she faces American Victoria Duval.
11.42pmThere's still plenty of top tennis to come as the US Open enters its late session. A couple of big hitters kick-off their campaigns tonight as Kim Clijsters and Roger Federer get going at the Arthur Ashe Stadium.
11.36pmIn truth Sharapova couldn't have asked for a better start to her US Open. A number of long rallies to blow away the cobwebs and a confident, measured performance. The Russian is definitely a contender in the women's tournament.
11.34pmA smart shot to the baseline keeps Czink alive, but its only a momentary reprieve. Sharapova takes the match with the very next point to win 6-2 6-2.
11.33pmCzink goes for broke but misses a forehand winner. Two match points for Sharapova.
11.29pmThe Russian crashes home another big return to take the game and make it 5-2 in the second. Sharapova will now serve for the match.
11.28pmThat rally forced Sharapova to up her game and she earns break point with a lovely slice disguised into the corner. No chance for Czink there, which has been the case for much of the match.
11.26pmCzink digs deep and wins the best rally of the match. A wonderful rally of more than twenty shots forces Sharapova wide and Czink finishes in style to rapturous applause.
11.24pmSharapova shows her class to find a way to hold and she restores a two-game lead in the second set.
11.23pmCzink looks to have figured out Sharapova's serve at long last. An absolute rocket from the Hungarian sends the game to 30-30.
11.21pmSharapova is running the risk of turning this match into a genuine contest with a series of unforced errors. Time to regain her composure if she wants to take this first-round match in straight sets.
11.19pmCzink needs to find a way to hold serve now if she wants to keep her US Open alive. The Hungarian shows some nice variety to cut the deficit to one game in the second set.
11.16pmA rare Sharapova error hands Czink the break and we are back to 3-1 in the second. Maybe this match is not over after all.
11.15pmFinally Czink finds some joy on Sharapova's second serve and has a break point.
11.13pmSharapova is not being threatened on serve and could wrap this match up very quickly. A couple of unforced errors give Czink a rare chance to make deuce.
11.08pmCzink looks stunned as she finally wins her first point of the second set in the third game. It's not enough to halt Sharapova's charge as she takes a 3-0 lead.
11.04pmMaria is absolutely relentless as she continues her assault on a helpless Czink in the second set. She races into a 2-0 lead in the blink of an eye.
10.02pmA pair of delightful winners on his trademark double forehand and Murray has match point.
10.00pmBogomolov looks like he can't wait to get out of here. His struggles on serve continues as he is broken again. Murray now leads 5-1 and will serve for the match.
9.56pmThe Scot finds a pair of baseline winners to close out a tough service game. He leads 4-1 but Murray looks in some discomfort. Time to wrap this one up I think!
9.55pmMurray struggles to make a drop shot and goes down with what looks like cramp. Both men suffering in humid conditions.
9.53pmOnce again Murray makes life very hard for himself on serve. A couple of sloppy points hand Bogomolov two break points. Ivan Lendl watches on with an air of disapproval.
9.49pmUnfortunately for Bogomolov his mistakes on serve have been have frequent and untimely. His weakness on second serve is exposed once again and Murray is back in the driving seat. He leads 3-1 in the third set.
9.47pmMurray will be frustrated this match still has a glimmer of life left. He smashes home a nice return to take a 30-0 lead and the pressure is right back on Bogomolov.
9.46pmBogomolov has called for the doctor. He will need every ounce of strength to build on that impressive break.
9.43pmHow wrong I was, Bogomolov makes his break point count. Still some fight left in the plucky Russian, he trails 2-1 with the third set now back on serve.
9.42pmMurray is plagued once again by a sloppy second serve, break point Bogomolov.
9.40pmBogomolov looks disheartened as an increase in wind speed makes conditions more difficult.
9.38pmAn exceptional baseline lob earns Murray break point number four. He finally makes it count with a double-handed backhand to get the crucial hold.
9.36pmThe forehand winners are starting to flow now for Murray, but he spurns three break point attempts in a topsy-turvy game.
9.32pmMurray sends another scorching return down Bogomolov's throat to earn a break point.
9.29pmThe Russian world number 73 really needs to dig deep on serve, but he is struggling to match Murray's intensity. A whopper of a forehand makes it 30-30.
9.27pmA straightforward hold gives Murray a foothold in the third. Two sets and one game up with only a 58% success rate on his first serve.
9.25pmYou feel Bogolomov Jr needs to make a strong start to the third set or this match will slip away. A couple of unforced errors early on do not help his cause.
9.22pmTeam Murray can breathe a huge sigh of relief after another indifferent showing ends in a winning set. Begomolov Jr. just doesn't have the weapons to capitalise on an under-par performance from the Scot.
9.21pmBegomolov Jr throws caution to the wind and gets punished. Murray swats a huge shot right on the line to win the second set.
9.19pmAn uncharacteristic forehand error from Murray and we are back to deuce.
9.17pmMurray shows a marked improvement in energy at the baseline to earn a set point.
9.15pmBogomolov starts his service game strongly, two winners make it 30-0 in rapid time.
9.14pmWe finally see a series of formidable serves from Murray at just the right time. Bogomolov Jr. is now serving to stay alive in the second set.
9.11pmMurray's aggression is rewarded with a vital break. That could turn the tide in the second set, which is now leveled up at 4-4.
9.09pmBreak point Murray, more success at the net. That has been a major plus point for the Scot today.
9.08pmThe 29-year-old Russian is really digging in on serve in this set. A fine smash makes it 30-30 in a crucial game.
9.07pmMurray gives it some of old Lleyton Hewitt "come on" magic as he sends a winner down the line. He desperately needs to find a break or this second set will slip away.
9.04pmA strong hold from Murray and he cuts the deficit to one game, he now trails in the set 4-3.
9.03pmMurray ups the ante and delivers his finest shot of the match, a magnificent running forehand. He will need more of that to wrestle back the advantage in this set.
9.02pmBogomolov Jr. holds off an aggressive Murray charge to hold an important game. The Russian now leads 4-2 in the second set.
8.59pmElsewhere Kei Nishikori is the first man safely through to round two, beating Grand Slam debutant Guido Andreozzi in straight sets.
8.57pmA tough exchange but Murray digs deep to send his service game back to deuce. A huge first serve followed by a nice cross-court backhand gives him the game. That was an important hold for the third seed.
8.54pmMurray goes back to the drop shot and this time its too predictable, sending him 15-40 down on serve.
8.51pmBogomolov makes a couple of aggressive moves to the net and forces errors from a lethargic Murray. He holds to go 3-1 up in the second set.
8.49pmTime for Murray to pick up the pace and put some pressure back on Bogomolov's serve. A contentious call from the umpire has Murray up 0-30 on the Russian's serve.
8.45pmThe Scot cuts a frustrated figure as he slams a forehand wide. Murray quickly redeems himself with a strong first serve to close out his first game in the set.
8.42pmMurray is firing a whole host of expletives across the court as Bogomolov Jr. wraps up his first service game to love. That makes it 2-0 early in the second set to a rejuvenated Russian.
8.40pmBogomolov earns the early break with a tidy shot, much to Murray's annoyance. As if his displeasure wasn't obvious, he throws his racket to the floor in disgust.
8.38pmOnce again Murray goes to that trusty drop shot and we are back at our old favourite deuce.
8.37pmA change of shirt for the Russian and a change in fortunes. He has break point in the opening game of the second set after a poor smash from Murray.
8.35pmThat first set won't have Roger or Novak running for the hills but its the result that counts at this very early stage of the tournament. Murray starts on serve in the second.
8.34pmAfter being broken twice early on Murray maintained his composure and took the first set in 44 minutes. He looked relaxed as Bogomolov Jr. leaves the court.
8.31pmMurray makes no mistake with a forehand to earn a fourth break of the match and with it the first set. It has been far from vintage Murray but it's still enough to go a set up.
8.30pmIn only the first set Bogomolov Jr. decides to stop running as Murray plays a drop shot. That is a worrying sign for fans of the Russian. Set point to Murray
8.15pmAfter half hour of untidy play Murray is ahead for the first time, he holds serve to lead 3-2.
8.13pmA frustrated Murray is forced to deuce for the fourth time in the service game. The first set could still go either way at this stage.
8.11pmMurray avoids the break with a timely first serve. But an error in the next rally hands the Russian another opportunity to break.
8.10pmAnd its yet another break point, this is quite incredible. A great drop shot from Bogomolov Jr. is just too good. 30-40
8.08pmReally important now for Murray to get his first hold and make some first serves to take some early pressure off.
8.06pmAnother great exchange at the net but Murray has the edge. That makes it four games and four breaks. All square at 2-2 in a strange start to proceedings.
8.03pmAnother top forehand from the Russian keeps the game alive, back to deuce.
8.02pmMurray looks a little bit nervous but an unforced error from his opponent hands the Scot a break point.
8.00pmBogomolov Jr. is back on serve as he looks to earn the first hold of the match. He begins by winning a superb point as both players exchange a series of drop shots at the net.
7.57pmAn awesome return seals a second early break for the Russian, and in truth it was far too easy. He leads 2-1 in the first set.
7.56pmSuperb play from Bogomolov Jr. on his forehand forces two more break points. Worrying early signs for Murray.
7.54pmMurray needs to settle on serve as he looks to find some form.
7.53pmA huge forehand secures Murray the game, it was all to easy thanks to some sloppy serving from the Russian. 1-1 with two breaks of serve in the early going.
7.51pmA sign of tension from Bogomolov on serve makes it 15-40. A chance for Murray to break back instantly.
7.50pmWell that is definitely not the start the Scot wanted, a loose shot hands the opening game to the Russian underdog.
7.49pmEarly trouble for Murray, Bogomolov Jr.'s pace has earned him two break points.
7.47pmMurray is first to serve on the Arthur Ashe court as the match gets underway.
7.46pmHere at Sports Mole we will also keep you updated with Britain's Heather Watson as she serves to stay in the match against world number eight Li Na. That match is due to resume in 15 minutes.
7.45pmBogomolov Jr. enjoyed his best singles grand slam at Flushing Meadows last year, reaching the third round. His major attribute is a fleet-footed style across the court, a style Murray will need to deal with in the early going.
7.44pmA little bit of background on Murray's opponent this evening, Alex Bogomolov Jr, who is ranked at 73rd in the world. The Russian lives in Florida, and played for the US before switching allegiance back to his native country earlier this year.
7.39pmAnd here he comes, Murray is out on court at the Arthur Ashe Stadium warming up. In just a few minutes time we will have finally have some live tennis to get excited about.
7.38pmMurray has been on a rollercoaster during 2012, avenging defeat at the hands of Roger Federer at Wimbledon by crushing the Swiss champion in the Olympic Games Final.
7.33pmLet's hope Murray can put on a real show and make up for lost time. Bogomolov Jr. is a player he has lost to on one previous occasion, at the Sony Ericcson Open in Miami last year.
7.30pmAn official update has been released, we can expect Andy Murray on court within 10 minutes. Rejoice
7.26pmWatson briefly threatened to level the match up in the second set, earning a break that was quickly cancelled out by an in-form Li. The Chinese grand slam winner has played some fantastic shots from the baseline and richly deserves her lead.
7.22pmAnother Brit in action when play gets underway will be Heather Watson. The 20-year-old trails ninth seed Li Na 6-2 5-3 and it could be a short stint back on Court 17 unless Watson can turn the tide.
7.19pmLooks like we're finally getting close to play resuming on Arthur Ashe. Mercifully the rain has stopped. A quick reminder it will be Andy Murray time soon enough!
7.14pmIt's always quite a sight to see dozens of staff mopping up the floors of Flushing Meadows after a downpour. With a roof on centre-court at Wimbledon and a third roof currently being built at the Australian Open, the US Open is certainly at risk of being left behind in terms of top-level facilities.
7.10pmQuick stat attack for you, the US Open has been forced into a third Monday for four successive years now. If we continue to see weather like this in New York a fifth year of Monday-night finals looks increasingly likely.
7.04pmWith six matches due on the Arthur Ashe on day one lets hope a slow burner of an opening day will burst into life when some of the game's star names come out to play.
7.02pmIt looks like we are edging ever closer to play after a lengthy delay. A team of workers are currently attempting to get the Arthur Ashe court dry in preparation for Andy Murray's match against Alex Bogolomov Jr. Expect play within the hour, we hope.
6.49pmCroft is joined in the studio by Greg Rusedski. He enjoyed the high point of an impressive career at Flushing Meadows, making it all the way to the final in 1997. He ultimately lost to Australian Rat Rafter in four sets.
6.44pmLuckily we've been spared any Cliff Richards impersonations in New York. The British viewing public currently have the option of listening to Annabel Croft's musings on the fortnight ahead. It could be much, much worse.
6.38pmThe rain is subsiding at Flushing Meadows but we are still not ready to get back underway. Surely it's time for the US Open to follow Wimbledon's lead and put a roof on one of the show courts?
6.34pmTwo other women have also secured an early passage to round two, with Lucie Hradecka and Casey Dellacqua both winning in straight sets.
6.30pmFormer Wimbledon finalist Maria Bartoli is also on the verge of a place in the second round, earning a 6-3 6-6 lead against American Jamie Hampton before the rain came lashing down.
6.28pmAmerican eyes have been watching James Blake, and the veteran has not disappointed. He leads Slovakian Lukas Lacko 7-5 6-2 on the Louis Armstrong.
6.19pmHeather Watson was first out on court 17 against world number eight Li Na, and trailed 6-2 5-3 before rain stopped play. Watson is really up against it as she looks to keep her US Open challenge alive.
6.17pmRobson takes on American qualifier Samantha Crawford and has every chance of progressing to the second round. Fingers crossed Laura!
6.15pmIt's also a day to continue a patriotic summer of British sport as Laura Robson joins Heather Watson and Murray in getting her tournament underway.
6.13pmAfter an almighty deluge around 30 minutes ago, the conditions have finally improved slightly and hopefully play will be back under way soon enough. A whole host of superstar names are in action this evening if the weather continues to subisde. We've got Murray, Federer and Sharapova to look forward to tonight.
6.10pmA quick weather update from Flushing Meadows. If you were wondering why we're chatting incessantly about all things off the court, rain has brought a delay to proceedings on day one of the US Open.
6.05pmMurray will need to ride a wave of momentum to get back to the final at Flushing Meadows after being handed a tough draw. He could face tenacious Frenchman Jo Wilfried-Tsonga in the quarter-finals before he can think about tackling Djokovic or Federer in the latter stages.
6.00pmThe bookies also have Murray behind traditional nemesis Roger Federer as third favourite, despite his superb victory against the Swiss star in the Olympic Games final at Wimbledon.
5.56pmBack on the men's side of things, Murray is missing one major rival after Rafa Nadal's withdrawal with injury. He will still have to contend with the deadly duo of Roger Federer and Novak Djokovic as he aims for that elusive maiden grand slam title.
5.53pmHeather Watson is currently trailing ninth seed Li Na 6-2 5-3 over on court 17. The 20-year-old will need an incredible upturn in fortunes to hang on against the former French Open winner.
5.50pmMurray was due to kick off his campaign against Alex Bogomlov Jr. at 6pm on the Arthur Ashe court. Weather experts at Flushing Meadows are currently predicting a 45-minute delay to proceedings.
5.46pmIf you're joining us here at Sports Mole waiting for news of Andy Murray's opening US Open match, heavy rain has brought a delay to proceedings at Flushing Meadows.
5.38pmNew York has wasted no time in keeping things interesting, we have a rain delay less than two hours into the 2012 US Open. In the meantime we'll take a look at the runners and riders over the next fortnight.
5.35pmFingers crossed its a passing shower, if not Murray's 6.00pm start is definitely under threat.
5.33pmWow the rain is absolutely ferocious. Fans and officials run for cover as Flushing Meadows is the target of some awful conditions.
5.31pmAnd the rain that has threatened for the past hour has finally arrived. Play has been suspended as the heavens open.
5.30pmThe clouds continue to grow in stature above court 17 as Watson fights to keep this match alive. Li holds to put herself one game away from a straight-sets victory.
5.28pmJames Blake is rolling back the years in the Louis Armstrong stadium. The 32-year-old is a set and a break up against Lukas Lacko of Slovakia.
5.25pmLi wastes no time in securing a vital break, she now leads 6-2 4-3. Will take a huge effort from Watson to turn the tide now.
5.24pmThe World number 71 now needs to dig deep, she is trailing 0-40 on serve here.
5.22pmLi holds off a strong effort from Watson to level things up in the second set. We're at 3-3 as the match enters an important stage.
5.21pmSuperb effort from Watson as she produces some delightful shots at the net to come back from 40-15 to deuce at a crucial point in the second set.
5.18pmThe clouds are gathering in ominous fashion across Flushing Meadow. Don't you dare, Andy Murray is due on court in less than an hour now.
5.17pmAnd back on Court 17 Watson has been broken straight back by a determined Na. The Chinese ninth seed is still 3-2 down in the second but we are back on serve. Chance missed for Heather.
5.11pmAn early double fault from Heather and we are at 15-30 in the fifth game. Absolutely vital the Brit holds here.
5.10pmAnd Watson has done it, takes the break of serve at the third attempt and she is now right back in this match. 3-1 up now in the second set.
5.08pmSuperb baseline strike from Watson and she has three break points.
5.07pmA chance for Watson as she goes 0-30 up on Li's serve.
5.05pmAnother spirited effort from the 20-year-old, a strong serve keeps her ahead at 2-1 in the early stages of the second set.
5.04pmWatson is under pressure again on serve as Na takes her to deuce.
5.02pmJames Blake has given the American crowd something to shout about as he takes the first set 7-5 against Lukas Lacko on the Louis Armstrong.
5.01pmDelightful drop shot from Watson gives her some encouragement, 30-15 in the third game of the second set. Still on serve at 1-1
4.58pmNa continues to mix her game up nicely to keep Watson off guard. Keeping the Guernsey native off balance has been the key to her success so far.
4.55pmElsewhere in the women's singles Maria Bartoli has raced into a strong lead against American Jamie Hampton, leading 6-3 3-0.
4.54pmNice to see Watson respond well as she looks to make a fight of a tough match. She dug deep to hold serve in the opening game of the second set despite a third double fault.
4.51pmNa looked in formidable form in that first set, producing a phenomenal 89% success rate on her first serve.
4.50pmSet point for Na is duly dispatched, a relentless pace has earned her the first set 6-2 in 36 minutes. Watson will need to respond quickly to stay in this match.
4.48pmStosur has wrapped up the first set in double-quick time against Martic 6-1. A repeat performance in the second and Andy Murray may be in action earlier than expected. He follows this match on the Arthur Ashe.
4.45pmWatson is wilting in the first set against the ninth seed, losing a third successive game to go 5-2 down.
4.43pmOnly one match of interest early on in the men's half of the draw for a patriotic home crowd. The vastly experienced American James Blake is up against Lukas Lacko of Slovakia on the Louis Armstrong. That match is still on serve at 4-4.
4.41pmNa has given the 20-year-old no chance of a break, winning on serve to love to make it 4-2.
4.40pmWatson now needs to settle down and aim for a quick break back. Perhaps a tad too defensive on the baseline in the early going.
4.38pmA strong serve from Watson but Na doesn't let her off the hook, forcing a mistake to take the first break of match. 3-2 in the opening set.
4.35pmNa has picked up the pace against the British youngster, earning two break points.
4.34pmElsewhere on the Arthur Ashe Sam Stosur is wasting no time against Petra Martic, the Australian racing into a 5-0 first-set lead.
4.33pmTouch heavy on the return from Heather and Na is off the hook. Chance missed and the match stays on serve.
4.31pmNa regains her composure to swat the ball aside, back to deuce.
4.30pmAnother excellent deep return from Watson forces break point.
4.29pmBrilliant attacking forehand from Watson puts the pressure right on Na on serve, forcing an error to take the game to deuce.
4.26pmWatson stayed strong to hold serve in the third game, forcing a couple of cheap points from Na to make it 2-1.
4.20pmWatson has made a decent start against Na, the match going with serve in the very early stages at a game apiece.
4.19pmMurray is second up on the Arthur Ashe at around 6.00pm. Maria Sharapova, Kim Clijsters and Roger Federer are all to follow on a bumper opening day.
4.16pmMurray begins his quest for that elusive first grand slam title against Alex Bogomolov Jr. The Russian has a good record against Murray and beat him in straight sets at the 2011 Sony Ericsson Open.
16.12Watson is first up and faces a tough challenge against ninth seed Li Na over on Court 17.
4.10pmBritish interest is strong on day one at Flushing Meadows, with Andy Murray in action along with Heather Watson.