Live Commentary: Sorana Cirstea vs. Heather Watson - as it happened

Good afternoon! British number one Heather Watson and Romania's Sorana Cirstea are due on court shortly at Flushing Meadows for their first-round match at the US Open. The 22-year-old will be hopeful of securing her first win at the event against the world number 80.

The players have just arrived on court 13. It's pretty quiet around the ground so far, but is only 11am local time. It looks like it's going to be another warm, dry day in New York, which should suit the Brit, who spent much of her junior career based in Florida.

While the players are completing their warm up, let's have a look at their previous meetings. This will be the fourth time that these two players have faced each other. Watson is yet to lose to Cirstea, with all three of their previous meetings coming on hard courts. Their last meeting was in the Fed Cup earlier this year, when Watson came from a set down to beat the Romanian.

Watson has been in superb form this year. Having struggled with illness and injuries in 2013, the Guernsey-born player has broken back into the top 100, won her third title, and currently sits just a few places below her career-high ranking of 39. A win here today could help the former junior champion at the US Open jump into the top 40.

The players are ready to get the match underway, with Cirstea to serve first.

Cirstea makes a bright start, coming inside the baseline to put Watson under pressure to open up a 40-15 lead before the Brit return a serve long to give her opponent a comfortable hold.

It's a comfortable first service game for the world number 46. Her first two serves are returned wide by Cirstea, before Watson secures the first ace of the match. The Brit has a powerful serve, and it looks like it could cause the Romanian some problems on the return.

Cirstea is barely tested as she cruises to another hold of serve, finishing the game with back-to-back aces. It still looks like both players are easing themselves into this tie, with neither really pushing for an early break.

BREAK! A couple of superb returns from Cirstea put the Brit under pressure, but a stunning forehand down the sideline from Watson pulls the game back to 30-30. Cirstea commands a lengthy rally from the baseline on the next point though to bring up the first break point of the match, and the Brit gives the game away with a double fault. She'll be disappointed with that game.

It still looks pretty comfortable for Cirstea as she consolidates the break. Watson works hard from the back of the court as she tries to put her opponent under pressure, but the Romanian's dominant forehand clinches the game for her.

BREAK! It's four games in a row for Cristea! At 15-15, Watson times a cross-court forehand superbly to edge ahead, but a powerful backhand from Cirstea levels the scores before Watson fires long to give her opponent a chance to break again. A big serve takes the game to deuce, but a double fault from the British number one gives Cirstea another chance. Watson keeps herself in the game, coming inside the baseline to fire onto to sideline before hitting another ace to give herself advantage. Cirstea takes it back to deuce before sending two superb forehands to the back corner to clinch the game.

Having looked comfortable in her opening service game, Watson has struggled, getting just 50% of her first serves in, and winning just a quarter of the points off her second serve. She needs to get both of those stats up to get herself back into this match.

Cirstea looks like she's still getting stronger on serve as she races to a 40-0 lead. The Romania completely mis-hits a volley while trying to wrap the set up, but clinched the opener with an ace on the next point.

BREAK! Cirstea makes a superb start to the second set with a powerful backhand to the back of the court, before a mistake from Watson gives her a 30-0 lead. A wide forehand from the world number 46 brings up two break points for Cirstea, but she needs just one to clinch the game. That's six in a row for the Romanian now.

BREAK BACK! Watson produces some brilliant shots, which she desperately needs to, to give herself a 30-15 lead, but Cirstea gets a lucky hit off the net chord to take the next point. However, it goes in Watson's favour in the next rally to give her her first break point of the match, and Cirstea slices the ball into the net to let Watson get the set back on serve. Could this be the start of the comeback?

BREAK! Watson starts the game with a double fault before some superb returns from Cirstea bring up three break points for the world number 80. A long forehand allows Watson to save the first, but another double fault gives the Romanian the game. Watson really doesn't look herself at the moment.

Watson tries to get on the attack and break back again, but she misses several returns to give Cirstea a comfortable hold, despite the Romanian missing a couple of first serves along the way.

BREAK! Watson serves well to take a 40-30 lead, but Cirstea gets the better of the Brit in a long rally to bring up deuce. The Romanian blasted a forehand long to give Watson advantage, but a string of misses from the 22-year-old gifts her opponent the game and another break. Watson has held serve just one in this match so far.

Cirstea is just one game from a place in the second round now, breezing through another service game to leave Watson serving to stay in the match.

Two more double faults from Watson helped Cirstea bring up two match points.

What a hugely disappointing afternoon for the British number one. She's out of the US Open at the first round, as Romania's Sorana Cirstea sweeps her aside in just 54 minutes.

Watson has been in superb form recently, so such a heavy defeat was really unthinkable before the start of the match. Maybe we'll hear in her post-match interviews of an injury or illness that she has been keeping quiet. However, let's take nothing away from Cirstea, she's struggled for form in 2014, but served superbly and showed plenty of aggression and determination to progress.

Well that's all from this match, but stick around to follow live scores and read match reports from all of the top seeds in action at Flushing Meadows today. Until next time, thanks for joining me this afternoon, goodbye.