7pmPerhaps the most notable absentee from Chelsea's squad is Juan Mata. The Spaniard has been one of their most effective players in the final third this season.
7.03pmJosh McEachran, Kieron Dyer and Sammy Ameobi are all ineligible for the hosts so miss out, while Jonathan Woodgate, Lukas Jutkiewicz and Julio Arca are all struggling with injuries.
7.06pmIn the league, Middlesbrough are currently seventh in the Championship table, just one place and one point outside the playoff places. Meanwhile, Chelsea are fourth in the Premier League, two points clear of Arsenal following their loss the Manchester City at the weekend.
7.09pmIn three of the last four seasons, Tony Mowbray's side have been knocked out of the FA Cup by Premier League opponents, while Chelsea have beaten the last 10 Championship clubs that they have come up against.
7.14pmOne player desperate to win a cup competition is Chelsea striker Demba Ba, who has never lifted silverware with any of his previous clubs. Ahead of the match he told Chelsea's website: "Anyone can look on the internet and know I didn't win anything in my career, so I am getting hungry.
"In the past my clubs have taken the league more seriously than the cup competitions, and I didn't win anything yet. But now I am at Chelsea I am not afraid of the next years."
7.17pmMiddlesbrough have been hoping for their biggest crowd of the season for tonight's game. This afternoon, the club announced that they had sold 25,500 tickets for the match, and are hoping to beat the 28,229 that turned out for their clash with Sheffield Wednesday earlier in the season.
7.20pmIf Chelsea were to lose the tie, it would leave as many Championship clubs in the quarter-finals as top flight sides. Boro could join Barnsley, Millwall and Blackburn Rovers in the last eight of the competition.
7.23pmThe quarter-finals are due to take place next weekend. However, a draw this evening would result in a replay at Stamford Bridge, which would surely delay the fixture against Manchester United.
7.26pmIn the other quarter-finals, Manchester City will play Barnsley, Millwall host Blackburn Rovers and Everton will make the short journey to the DW Stadium to face Wigan Athletic, following their win over Oldham in a replay at Goodison Park last night.
7.30pmLet's have a quick look at the weather conditions at the Riverside. According to the latest report it is a chilly three degrees at the ground, but there is a 0% chance of rain.
7.34pmUnderstandably, the bookmakers make Chelsea the favourite for tonight's game, with several offering odds of 4/7. A draw is 3/1 while a Boro win is the least likely result with the bookies, with many giving odds of 9/2 and 5/1.
7.39pmMiddlesbrough's recent mixed form has largely been down to goalscoring. Tonight's hosts have netted just three times in their last four games. Chelsea have scored five goals in their four most recent ties.
7.42pmThe players are heading out to the pitch ready for the game. Bizarrely, Benitez appears to be greeted by an autograph hunter.
7.45pmThe teams are in formation and ready to go, it looks like we're just a few seconds away from kickoff.
2 minIt's Chelsea who are on the attack early, with Ake looking to cross the ball in to the Middlesbrough box, but Steele is alert, and comes off his goal line to take the ball.
4 minChelsea are continuing to keep the ball well, but have yet to really test the home side's defences. Both sides still seem to be finding their way into the game.
6 minAke is looking sharp early on for the visitors. He picks out Torres on the edge of the box, who passes to Oscar, but Middlesbrough make the clearance.
7 minMiddlesbrough win a free kick near the half-way line and look to push up the field, but Chelsea get the ball back and Torres makes a brilliant run down the wing, but he loses the ball before he can get a cross in.
8 minCHANCE! Oscar gets the ball just outside the box and goes for goal. It's a clever little chip to beat the Boro back four, but the end result is just wide of the goal, although it looked like Steele had it covered.
10 minMoses wins the first corner of the game for Chelsea. Oscar whips the ball in, but it's cleared, giving Chelsea a throw in just inside the Middlesbrough half.
12 minMcDonald picks up the ball for the hosts and looks to press towards goal. However, he's brought down inside the centre circle, resulting in a free kick for Boro. McDonald thinks he is through on goal on the edge of the area, but the assistant raises his flag, as the striker had just drifted ahead of the last defender.
13 minChelsea launch a quick counter-attack, and Steele is needed to make a good save. Both sides looks keen to get the first goal.
15 minJohn Terry gives away a free kick following a clumsy collision, and Middlesbrough are pushing for their first shot of the game. However, Chelsea are well organised at the back, and the hosts are forced to pass backwards in order to keep possession.
17 minLeadbitter looks to get a shot away for the hosts, but Ramires makes a block and clears. Middlesbrough are starting to see more of the ball now, but have yet to really trouble Chelsea.
18 minFriend is brought down around 30 yards out, giving Middlesbrough a free kick. The ball drops to Bailey who looks for a header, but the ball is too high and he can't get control in time, allowing Chelsea to get the ball away.
20 minTerry passes the ball back to Cech who boots the ball out for a throw in, leaving Middlesbrough in a strong attacking position, but a poor pass from Leadbitter gives the ball away.
21 minFernando Torres has a half-chance for Chelsea, picking the ball up inside the penalty area. However, the Spaniard's shot lacks power, making it an easy stop for Steele.
24 minA failed pass forward falls to Leadbitter, who picks out Main, but the pass drops too far forward and Main stumbles trying to reach the ball and it goes out.
26 minCHANCE! Bailey whips the ball in for McDonald, whose header goes just inches wide. That's Boro's best chance so far, following a strong, attacking spell from the hosts.
28 minChelsea seem to be struggling to penetrate Middlesbrough's defence at the moment. The majority of Chelsea's possession in the last 10 minutes has come from passes amongst the back four, while passes forward have largely been picked up by the hosts.
30 minChelsea eventually break through the midfield, and Oscar has a chance from the edge of the box but Friend is there to make the clearance. Ake ties to slot the ball back in moments later, but once again it fails to find a blue shirt.
33 minRafael Benitez is furiously barking orders from the sideline. After a positive start, his side have been second best for much of the 33 minutes played so far.
35 minChelsea win a corner and Oscar delivers the ball, but it comes back out, giving him a second chance, but again it's cleared.
37 minSUBSTITUTION! Middlesbrough have been forced in to an early change. Andre Bikey has gone off, with Seb Hines coming on in his place. The defender has been struggling with his movement for the last few minutes.
39 minHaroun takes a curling shot from distance, but it's an easy save for Petr Cech. It may have been going wide anyway, but the Chelsea keeper made sure. Despite Boro's positive display, it's been a quiet opening spell for Cech.
42 minBoro have another injury concern. Leadbitter is on the charge for the hosts but is brought down, and it looks like he's turned his ankle. The physio is taking a good look at the affected area.
44 minHaroon feeds the ball in from distance, with players waiting in front of goal, but Cech comes out from his goal the gather the ball. Middlesbrough are ending the half strongly.
45+1 minChelsea appeal for a penalty after Victor Moses goes down in the area, but there was no contact and the referee awards a corner, which Middlesbrough clear with ease as the game heads into two minutes of stoppage time.
8.35pmIt's difficult to say which side will be happiest at the break. Middlesbrough will be pleased to have matched their Premier League opponents, but disappointed not to have a lead despite having created the better chances.
8.38pmMiddlesbrough had three shots to Chelsea' one in the opening 45 minutes. Scott McDonald probably spurned the best of those chances with an off-target header.
8.40pmNathan Ake and Oscar both looked sharp for Chelsea, but passing from the back four let the visitors down on the counter attack, as Middlesbrough regularly picked the ball up in midfield.
8.45pmThe home side will have to be careful not to pick up too many knocks as the game goes on. With Andre Bikey having to go off in the first half and Grant Leadbitter having already been treated for an ankle injury, Boro may have to make their changes early in the second half.
8.48pmThe players are heading back out for the second half. Both will be keen to avoid the replay.
52 minVictor Moses broke down the right before passing to Oscar, whose effort was blocked, but the rebound fell to Ramires, who superbly volleyed the ball passed Steele to put Chelsea ahead.
53 minThe goal seems to have upped the urgency among the Middlebrough players, who quickly force a corner at the other end of the pitch.
55 minIt looks like to goal has boosted the visitors as well, as they push to double their league. Oscar looks to get a cross in towards the box, but it's cleared.
57 minMiddlesbrough are pushing towards the Chelsea goal again, but cup holders get numbers back to protect their lead, regaining possession and taking the ball immediately down the other end of the pitch.
59 minCHANCE! Fernando Torres beats the offside trap and finds himself one-on-one with Steele, but his effort strikes the top of the bar. However, it looks like Steele may have got a hand to it, giving Chelsea a corner.
61 minMiddlesbrough try a couple of long balls as they push for an equaliser, but they fail to control the ball inside the box, giving Chelsea a goal kick.
63 minSUBSTITUTION! Curtis Main is replaced by Ishmael Miller for the hosts.
65 minA replay of the goal shows that the ball took quite a deflection off Torres on the way in. The ball has been awarded to Ramires for now, but given the £50 million striker's lack of recent goals, he may try to claim it from his teammate.
66 minOn the sidelines, Frank Lampard has started warming up for Chelsea. It looks like he could be coming on shortly.
68 minMiddlesbrough have abandoned the long ball approach and have started to dominate the midfield again, but Chelsea's defence holds strong, preventing the hosts from getting a shot.
70 minTorres flicks to ball forward for Moses, before Williams puts it out giving Chelsea a throw in. Ferreira looks to get the ball into the box, but Middlesbrough make the clearance.
74 minHazard, who came on in place of Benayoun, takes his first shot of the game, which is cleared, but he managed to get the ball back and pulls it back for Victor Moses, who taps in from close range to give Chelsea a two-goal lead.
76 minCHANCE! Oscar almost makes it three after beating the Boro defence before firing the ball just wide.
77 minSUBSTITUTION! It's the second goal scorer who makes way, as David Luiz comes off the bench for Chelsea.
78 minSUBSTITUTION! Mustapha Carayol goes off as Middlesbrough make their final change, bringing on Merouane Zemmama.
79 minMiddlesbrough win a free kick, which Leadbitter fires into the Chelsea box, and is put out for a throw in.
80 minSUBSTITUTION! Chelsea make their final change as Marko Marin is brought on in place of Oscar.
82 minCHANCE! McDonald takes a shot from the edge of the area, but it goes wide. Middlesbrough have had few chances in the second half, but they're attacking well at the minute.
83 minChelsea give away a free kick just outside the area. Zemmama really gets behind the ball, forcing a solid save from Cech. That will have left the Czech's hands stinging. The home side haven't given up yet!
85 minCHANCE! Boro have a corner and McDonald goes up for a header, but it's wide. Moments later, Miller attempts to dink the ball beyond Cech, but his effort goes just high.
86 minThe attendance for the game is confirmed at 27,856, just short of a season high for the Riverside.
87 minBOOKING! Nicky Bailey picks up a yellow card after charging in to Nathan Ake, conceding a free kick to the left of the penalty area, but Boro clear the ball.
88 minTorres looks to be through on goal in pursuit of Chelsea's third, but the striker is flagged offside.
90 minCHANCE! Miller has another chance for Middlebrough, but he's challenged and the ball goes just wide, giving Boro a corner, which is cleared by Chelsea.
90+1 minLeadbitter finds Zemmama on the edge of the penalty area but his shot goes wide, giving Chelsea a goal kick. There will be three minutes of stoppage time.
90+3 minWilliams attempts a volley from the edge of the area for Middlesbrough, but he doesn't time it right, and the ball goes wide. Time is running out for the hosts.