West Ham United: Green, Neill, Collins, Upson, Ilunga, Collison, Parker, Noble (Nsereko 74), Boa Morte (Sears 49), Di Michele, Cole (Tristan 33)
Subs not used: Lastuvka, Lopez, Kovac, Spector.
Goal: Ilunga 83.
Middlesbrough: Jones, Hoyte, Huth, Wheater, Pogatetz, Adam Johnson, O'Neil, Digard, Arca (Walker 77), Downing, Alves (Sanli 74).
Subs not used: Turnbull, Emnes, Bates, McMahon, Bennett.
Goal: Downing 22.
93 min - Peter Walton blows for full-time. So the two sides will have to try all over again at the Riverside Stadium. The replay will be on Tuesday 24 February, with kick-off on Teesside at 8pm. Before then, the Hammers have the small matter of a Premier League fixture at Bolton Wanderers to deal with. Elsewhere in the FA Cup, Coventry have been denied by a late Blackburn equaliser at Ewood Park, while Sheffield United and Hull have drawn 1-1. Earlier, Swansea City and Fulham drew 1-1, meaning not one team is definitely through to the quarter-finals. Meanwhile, Portsmouth have beaten Manchester City 2-0 in the Premier League, so the Hammers remain eighth in the table.
91 min - Sears is penalised for a nudge on Pogatetz.
90 min - Di Michele takes a tumble on the red pitch surround after chasing a through ball, much to the crowd's amusement. There will be three added minutes.
89 min - Huth fouls Tristan. The Spaniard has held the ball up well. A loose ball falls to Sears inside the panelty area, but the youngster can only lash the ball high into the stand.
87 min - Di Michele is booked after Collins commits a foul. It is not clear what the Italian did wrong. It is his third yellow card of the season.
87 min - Savio has been lively since arriving. The Germany Under-20 man clearly has a few tricks in his locker.
85 min - Boro have a free-kick wide on the left after Di Michele commits a foul, but Collins risest highest to head the ball clear.
83 min - GOAL! O'Neil is made to pay for his mistake. Savio curls the ball into the penalty area. It eludes Collins' flick-on but bounces to the far post where Ilunga is on hand to head the ball into the roof of the net. It is the DR Congo international's second FA Cup goal of the season, having earlier scored in the third round win over Barnsley.
82 min - O'Neil handles the ball, then slams it high into the East Stand. Referee Walton books him for his troubles.
81 min - Downing lets fly with a left-foot shot, only for the ball to hit Tuncay and bounce out for a goal-kick. We're inside the final ten minutes. Can West Ham book themselves a trip to the Riverside Stadium?
80 min - West Ham have a corner. Savio will take it. Tuncay slices it out for another flag-kick. This time, Jones claims the high ball.
77 min - Hermann Hreidarsson has put Portsmouth 2-0 up over Manchester City. In the FA Cup, Coventry have taken the lead at Blackburn through Michael Doyle.
76 min - Close again! Jones is out smartly to deny Sears as West Ham pile bodies into the Boro penalty area. The visitors are preparing to make another change, with Josh Walker coming on to replace Arca.
75 min - West Ham are getting up a head of steam here. There is still enough time to force a replay.
74 min - Maybe it is not going to be West Ham's day. Collison finds Ilunga and his cut-back rolls into the path of Di Michele ten yards from goal, only for the Italian to sky his left-foot shot high into the Bobby Moore Stand. Savio is on for Noble, while Tuncay is on for Alves.
73 min - Green does brillianlty to keep out Downing's long-range shot. The goalkeeper also did well to scramble and prevent the ball rolling out for a corner. Savio is still waiting to make his entrance.
72 min - Good news for West Ham. Portsmouth are a goal ahead against Manchester City courtesy of former Hammer Glen Johnson. If Pompey win, West Ham remain eighth in the Premier League table.
71 min - Both sides are preparing to make a change. Savio is stripped off and ready to go for West Ham, while Boro have Tuncay Sanli on the touchline.
69 min - So close for the Hammers! Tristan swaps passes with Di Michele before skipping past a challenge, but the ball rolls just too far in front of him and Boro clear the danger.
68 min - Coventry City have drawn level at Blackburn. Aron Gunnarsson is the Sky Blues' scorer.
67 min - Savio and Walter Lopez are warming up on the touchline.
65 min - To be fair, Middlesbrough look the more likely side to score the game's second goal. Boro have made the FA Cup quarter-finals in each of the past four seasons and, as things stand, will make it five in a row.
64 min - Noble is robbed in midfield. Alves runs at Collins and unleashes a low shot, but Green goes down well to his right to keep the ball out.
63 min - Collison combines with fellow Academy graduate Sears down the right flank, but the striker's cross is too close to Jones.
60 min - Di Michele is robbed by Downing. The winger rolls the ball through the middle of the Hammers' back-four and Alves springs the offside trap, but his shot is low and wayward again.
58 min - Alves cuts between Neill and Collins and, despite having O' Neil and Downing free to his right, slams a shot at least 20 yards wide of Green's goal.
57 min - Arca is penalised for holding back Di Michele. Noble's free-kick is easily cleared, though.
55 min - Parker drives forward and finds Tristan 25 yards out. The Spaniard turns, but his shot is too high to trouble Jones.
54 min - Neill lobs the ball over the top for Di Michele, but the Italian is flagged for offside. It is just not clicking for the Hammers in the attacking third. Will things change in the final 35 minutes?
52 min - Downing slaloms past Parker and Collison only to be brought down. Boro have a dangerous free-kick 25 yards from goal. O'Neil finds Downing, but his cross is cleared by Collins.
49 min - Boa Morte is replaced by Freddie Sears.
46 min - A couple of things to report at the start of the second half. The referee has changed into a yellow kit as his black shirt clashed with Boro's black and blue away kit. Meanwhile, the attendance today has been announced as 33,658. Oh, and the match has started again.
HALF TIME - West Ham United 0-1 Middlesbrough
47 min - Peter Walton blows for the end of the first half, but not before booking Noble for a lunging tackle on O'Neil.
45 min - Boa Morte leads a counter-attack from a Boro free-kick. He finds Di Michele, who lays the ball into Tristan's path, but the striker can only slice his shot well off-target.
43 min - It just is not happening for West Ham as yet. Maybe the half-time break will bring about a change in fortune after the interval.
40 min - Huth is slightly fortunate. Collison lofts a through ball over the top for Parker to chase. The German attempts to clear and inadvertantly nutmegs Parker inside his own penalty area. Straight up the other end and Julio Arca brings Green into action again with a header from O'Neil's cross.
38 min - Tristan gets involved. He outpaces Hoyte to the loose ball before feeding Boa Morte. The Portuguese winger's low cross is deflected into the path of Noble, whose shot is well saved by Jones. Collison reacts quickest but launches his shot well over the crossbar from a tight angle.
37 min - Collins' loose header falls to Downing. He feeds Alves, but the Brazilian's low shot dribbles wide of the target.
36 min - Parker brings down Alves 30 yards from goal. Meanwhile, Kamil Zayatte has equalised for Hull at Sheffield United. Alves' free-kick hits the wall and is cleared.
34 min - A bit of a blow for the Hammers. Cole is unable to continue and is replaced by the Spaniard Diego Tristan.
31 min - Alves meets Hoyte's volleyed cross, but his header skims well wide and out for a goal kick.
28 min - Alves lets fly with a low shot that is deflected well wide for a Boro corner. O'Neil's centre falls back to the midfielder and his second cross is met by Huth's head, but Green is there to make the catch.
27 min - Cole receives treatment for a left leg injury. The striker then walks to the touchline for further assistance. Let us hope it is not too serious.
26 min - After the shock of conceding, West Ham go close to an equaliser. Di Michele beats two Middlesbrough defenders before unleashing a dipping volley from 25 yards that bounces past the Australian's left-hand post and into the Boro fans behind the goal.
22 min - GOAL! Football really is a funny old game. Alves leads a counter-attack and finds Downing on the left. He works the ball back out to O'Neil on the right wing. The former Portsmouth man crosses, the ball eludes Collins and Upson and England winger Downing is on hand to head past Green from close-range. That is a complete sucker-punch.
22 min - This is complete one-way traffic at the moment. Di Michele sees his shot blocked as West Ham continue to press.
21 min - Ilunga wins yet another corner. Noble takes again and, following a game of penalty area pinball, Didier Digard hacks the ball clear.
20 min - Boro cannot get hold of the ball at all. They have not been out of their own half for nearly five minutes.
18 min - Boa Morte foces Hoyte to concede a corner. Noble takes, but an unmarked David Di Michele is unable to make contact with an acrobatic volley. Seconds later, Jones flies to his right to repel James Collins' blockbuster. Surely an opening goal will arrive soon?
17 min - I told you it would liven up! Boa Morte and Collison combine to set up Noble, but Jones is alert and pushes aside his rasping shot.
16 min - Upson produces a fine sliding challenge to deny Alves. The England defender then does brilliantly to avoid touching the ball with his hands before stabbing clear.
15 min - There is not a huge amount happening here, to be honest. West Ham are showing signs that they may spring to life though. A quickly taken throw-in leads to Noble curling a shot into Jones' arms.
13 min - A first sniff of goal for England's Carlton Cole, but his effort is deflected behind by Huth. Mark Noble's corner is plucked out of the sky by Jones.
11 min - There have been two early goals in the other 3pm FA Cup kick-offs. Sheffield United are 1-0 up against Hull City thanks to Greg Halford, while Roque Santa Cruz has put Blackburn Rovers a goal up against Coventry City. Back at the Boleyn Ground, Downing fizzes a low shot narrowly wide of Robert Green's post following a fine run and pass from Gary O'Neil.
10 min - West Ham have made a slightly nervy start here. The home side have not found their trademark passing rhythm as yet.
8 min - Brad Jones hacks the ball into touch following a mis-directed backpass from David Wheater.
6 min - Gianfranco Zola is on the edge of his technical area issuing instructions to his side. Middlesbrough have started the better of the two sides, which will not be pleasing the West Ham manager.
4 min - Luis Boa Morte puts in a fine sliding challenge on Robert Huth, much to the home crowd's delight.
3 min - Justin Hoyte crosses low into the box, only for Afonso Alves to lose his footing, allowing Collins to clear comfortably.
2 min - A short pass from Jack Collison allows Stewart Downing to get in behind James Collins. His low cross is half-cleared by Matthew Upson, only to fall to Adam Johnson, but the England Under-21 man's shot flies well wide. That was a let-off.
West Ham have just one survivor from the memorable 1-0 FA Cup semi-final win over Boro three seasons ago. For the visitors, goalkeeper Brad Jones and Stewart Downing both featured at Villa Park on 23 April 2006.
Here come the two teams! Lucas Neill leads out the home side to the strains of 'Bubbles'. Emanuel Pogatetz is the Boro skipper.
The groundstaff are out forking the pitch as we approach the big kick-off. A win today would take the Hammers to within one victory of their first trip to the new Wembley Stadium.
It is approaching 2.50pm and the West Ham United players are heading for the home dressing room. A few of the substitutes have remained on the pitch and are firing shots at young goalkeeper Marek Stech.
It's a crisp, sunny day in east London. Both teams are completing their pre-match warm-ups on the Boleyn Ground pitch.
Swansea City and Fulham will both be in the hat for Sunday'sixth round draw. The pair have fought out an entertaining 1-1 draw at the Liberty Stadium.
Boro boss Gareth Southgate has switched to a 4-5-1 formation, with Gary O'Neill coming in for the cup-tied Marlon King. At the back, Justin Hoyte replaces the injured Chris Riggott, with England Under-21 defender David Wheater reverting to centre-half.
Hammers manager Gianfranco Zola has made just one change from the team that went down to a narrow 1-0 Premier League defeat to Manchester United six days ago. Valon Behrami, who has a slight hamstring injury, has been replaced by Luis Boa Morte. Walter Lopez has been named among the substitutes in Behrami's absence.
Kick-off is fast approaching at the Boleyn Ground, with West Ham United preparing to entertain Middlesbrough in the FA Cup fifth round.
Boro have not won in their past 13 Premier League matches, but have found their form in the FA Cup, knocking out non-league Barrow and Championship leaders Wolverhampton Wanderers to reach the last 16.
West Ham, meanwhile, have lost just one of their last nine matches in all competitions, beating Barnsley and Hartlepool United to reach this stage.