Second placed West Ham won their fourth successive match after goals from Frederic Piquionne and Carlton Cole earned them a win over Middlesbrough.
Piquionne headed in Matt Taylor's early cross although Hammers goalkeeper Robert Green had to be sharp to deny Scott McDonald an instant equaliser.
Tony Mowbray's Middlesbrough had not lost at home for 16 matches, but could not find a way past Green.
Cole rounded goalkeeper Jason Steele to seal the win in injury time.
Marvin Emnes looked the most likely home player to force a breakthrough, but he and McDonald were denied by Green as the first half drew to a close.
Mowbray's side increased their work-rate in the second period, and Faris Haroun shot wide after Joe Bennett played a dangerous ball into the penalty box.
West Ham could have increased their lead on the hour mark when Papa Bouba Diop was presented with a clear opportunity but shot wide instead of passing to Kevin Nolan - the former Bolton man would have loved to have marked his 400th career game with a goal.
Despite bringing on Bart Ogbeche, Julio Arca and Alex Nimely from the bench, Boro were to lose their unbeaten home record, and Cole secured all three points when he benefited from a poor Boro clearance.
The England striker rounded Steele and finished calmly despite the presence of two Boro defenders on the goal-line - sending the 1,243 travelling fans in to raptures as they celebrated their fourth straight win away from home.
After Middlesbrough's defeat, only Southampton and Birmingham now have unbeaten home records in the Championship this season.
West Ham manager Sam Allardyce said after the game: "We got every element right today. When we had to defend, we defended well, when we attacked, we exploited the spaces they were leaving to show our quality in the final third.
"We're a very happy bunch at the minute, we're just keeping our feet on the ground, enjoying our training and enjoying our time together. We prepared right for this one today."
Middlesbrough boss Mowbray was frustrated with his side's performance, saying: "It was one of those nights we huffed and puffed and had a few chances but I never really sat on the edge of my seat.
"They've got a lot of Premier League experience and I think it showed. We'll take it on the chin and move on."
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Live Text Commentary
Full Time The match has reached full-time.90:00 +3:03 Goal scored
Goal! - Carlton Cole - Middlesbro 0 - 2 West Ham Carlton Cole scores a goal from deep inside the penalty box to the bottom left corner of the goal. Middlesbrough 0-2 West Ham.90:00 +1:29
Mark Noble decides to take a short corner.90:00 +1:12
Matthew Taylor takes a shot. Julio Arca gets a block in.90:00 +0:44
Unfair challenge on Carlton Cole by Tony McMahon results in a free kick. Free kick taken by Mark Noble.89:55
Effort on goal by Julio Arca from outside the area goes harmlessly over the bar.89:47
Marvin Emnes produces a cross, clearance by James Tomkins.89:11
A cross is delivered by Matthew Bates, James Tomkins makes a clearance.87:51
The ball is sent over by Julio Arca.87:40
Centre by Tony McMahon, clearance by James Tomkins.87:17
Scott McDonald gives away a free kick for an unfair challenge on Papa Bouba Diop. George McCartney takes the direct free kick.84:04
Scott McDonald concedes a free kick for a foul on George McCartney. Robert Green takes the free kick.83:21 Substitution
Substitution Alex Nimely comes on in place of Merouane Zemmama.83:21 Substitution
Substitution Rhys Williams goes off and Julio Arca comes on.82:57
Julien Faubert delivers the ball, Effort on goal by Kevin Nolan from just inside the box goes harmlessly over the target.81:59
Stephen McManus takes the direct free kick.81:59 Booking
Booking Mark Noble booked.81:53
Kevin Nolan challenges Merouane Zemmama unfairly and gives away a free kick.79:14
The ball is sent over by Joey O'Brien, Stephen McManus makes a clearance.77:50
Mark Noble takes the direct free kick. Kevin Nolan delivers the ball, clearance by Matthew Bates.
Substitution Joey O'Brien on for Guy Demel.77:50
Tony McMahon gives away a free kick for an unfair challenge on Mark Noble.76:42
Corner from the right by-line taken by Tony McMahon, Papa Bouba Diop manages to make a clearance.76:27
Tony McMahon takes the outswinging corner, clearance by Papa Bouba Diop.76:05
Corner from the right by-line taken by Tony McMahon, Papa Bouba Diop manages to make a clearance.75:35
The ball is sent over by Papa Bouba Diop, clearance made by Stephen McManus.74:57
The ball is delivered by Papa Bouba Diop, free kick awarded for a foul by Carlton Cole on Matthew Bates. Stephen McManus takes the indirect free kick.74:01
Corner from the right by-line taken by Matthew Taylor, Bart Ogbeche manages to make a clearance.73:14 Substitution
Substitution Bart Ogbeche joins the action as a substitute, replacing Nicky Bailey.71:10
Effort from outside the penalty area by Nicky Bailey goes wide left of the target.68:50
Jason Steele is penalised for a handball. Matthew Taylor crosses the ball in from the free kick.67:36 Substitution
Substitution Frederic Piquionne goes off and Carlton Cole comes on.66:03
Tony McMahon produces a cross, James Tomkins makes a clearance.65:50
The ball is crossed by Joe Bennett, clearance by James Tomkins.65:25
Shot by Joe Bennett. James Tomkins makes a clearance.64:53
George McCartney gives away a free kick for an unfair challenge on Marvin Emnes. Tony McMahon takes the free kick.63:58
Effort from the edge of the area by Marvin Emnes goes wide of the left-hand post.62:54
Foul by George McCartney on Marvin Emnes, free kick awarded. Matthew Bates takes the direct free kick.62:46
The ball is delivered by Papa Bouba Diop, Matthew Bates manages to make a clearance.61:22
Centre by Tony McMahon, clearance made by James Tomkins.60:03
Outswinging corner taken right-footed by Tony McMahon from the right by-line, Headed effort from inside the area by Rhys Williams misses to the left of the goal.59:26
Papa Bouba Diop fouled by Marvin Emnes, the ref awards a free kick. Direct free kick taken by Kevin Nolan.57:54
Effort from deep inside the area by Papa Bouba Diop misses to the right of the target.57:40
Julien Faubert delivers the ball.54:23
Effort from outside the area by Faris Haroun goes wide right of the goal.52:45
Long distance shot from Papa Bouba Diop misses to the left of the goal.51:08
The ball is sent over by Joe Bennett, clearance made by James Tomkins.50:51
Free kick awarded for an unfair challenge on Nicky Bailey by Mark Noble. Direct free kick taken by Rhys Williams.48:11
Free kick taken by Robert Green.48:11 Booking
Booking Caution for Scott McDonald.47:55
Unfair challenge on James Tomkins by Scott McDonald results in a free kick.45:48
Effort from outside the box by Julien Faubert goes wide right of the target.45:17
Foul by Faris Haroun on James Tomkins, free kick awarded. Abdoulaye Faye restarts play with the free kick.45:01
The referee gets the second half started.45:00 +1:25 Half time
Half Time The half-time whistle blows.45:00 +0:24
The ball is sent over by Mark Noble, clearance made by Matthew Bates.43:31
Unfair challenge on Nicky Bailey by Frederic Piquionne results in a free kick. Free kick taken by Marvin Emnes.43:10
Inswinging corner taken right-footed by Tony McMahon from the left by-line, James Tomkins makes a clearance.42:51
Marvin Emnes takes a shot. Abdoulaye Faye gets a block in.42:16
The referee blows for offside. Free kick taken by Robert Green.41:59
The ball is swung over by Scott McDonald, save made by Robert Green.39:51
Unfair challenge on Scott McDonald by James Tomkins results in a free kick. Free kick crossed right-footed by Tony McMahon, Guy Demel manages to make a clearance.39:29
Matthew Taylor concedes a free kick for a foul on Tony McMahon. Jason Steele takes the direct free kick.37:33
Faris Haroun has an effort at goal from just inside the box that misses to the left of the target.37:02
The ball is sent over by Tony McMahon, clearance made by James Tomkins.36:08
Inswinging corner taken by Matthew Taylor, Joe Bennett manages to make a clearance.36:00
George McCartney sends in a cross, blocked by Marvin Emnes.35:46
George McCartney takes a short corner.35:39
Julien Faubert delivers the ball, clearance made by Matthew Bates.31:53
Scott McDonald takes the chance to get an effort at goal. Corner taken by Tony McMahon from the left by-line. Save by Robert Green.31:08
Inswinging corner taken right-footed by Mark Noble, Matthew Taylor has an effort at goal from outside the area missing to the wide right of the goal.30:04
Matthew Taylor has an effort direct from the free kick.30:04 Booking
Booking Stephen McManus goes into the referee's book for unsporting behaviour.29:58
Stephen McManus challenges Mark Noble unfairly and gives away a free kick.29:15
A cross is delivered by Merouane Zemmama.25:45
The ball is delivered by Marvin Emnes, Faris Haroun takes a shot. Save by Robert Green.25:33
The ball is delivered by Merouane Zemmama, clearance made by Papa Bouba Diop.25:25
The ball is delivered by Tony McMahon.24:52
A cross is delivered by Papa Bouba Diop.23:32
Merouane Zemmama concedes a free kick for a foul on Mark Noble. Julien Faubert takes the free kick.22:17
The offside flag is raised against Julien Faubert. Stephen McManus takes the free kick.20:20
Shot from long range by Matthew Taylor goes over the bar.17:58
Kevin Nolan is ruled offside. Jason Steele takes the free kick.17:21
Frederic Piquionne delivers the ball, Matthew Bates makes a clearance.15:25
Foul by Matthew Taylor on Faris Haroun, free kick awarded. Merouane Zemmama fires a strike on goal direct from the free kick.13:26
Scott McDonald takes a shot. Save by Robert Green.8:42
Mark Noble provided the assist for the goal.8:42 Goal scored
Goal! - Frederic Piquionne - Middlesbro 0 - 1 West Ham Frederic Piquionne scores a headed goal from inside the area. Middlesbrough 0-1 West Ham.6:52
Papa Bouba Diop concedes a free kick for a foul on Scott McDonald. Tony McMahon has a direct shot on goal from the free kick, save by Robert Green.4:41
Mark Noble sends in a cross, Joe Bennett makes a clearance.4:21
George McCartney sends in a cross, Matthew Bates makes a clearance.4:08
Centre by Mark Noble, Faris Haroun gets a block in.3:06
The ball is crossed by George McCartney, Stephen McManus makes a clearance.1:18
Unfair challenge on Kevin Nolan by Faris Haroun results in a free kick. Direct effort from the free kick comes in from Matthew Taylor, save by Jason Steele.0:12
Scott McDonald challenges James Tomkins unfairly and gives away a free kick. Robert Green takes the free kick.0:00
The referee gets the match started.
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