Tomas Rosicky scored in each half as 10-man Arsenal withstood a West Brom fightback to move above Chelsea into fourth place in the Premier League.
Rosicky cleared a Claudio Yacob effort off the line before putting Arsenal ahead with a powerful diving header.
The Czech midfielder struck again after half-time, drilling into the bottom corner at the second attempt.
James Morrison converted a penalty as Per Mertesacker was sent off for a foul on Shane Long, but Arsenal held firm.
They go a point clear of Chelsea in the final Champions League spot, but have played a game more than the Stamford Bridge club.
Rosicky on the mark
Tomas Rosicky scored his first Premier League goal for Arsenal since February 2012 and this was the first time he has scored more than one goal in a league game for the club
West Brom remain eighth, which would be their highest Premier League finish, but they have only won once in their last five top-flight games.
Arsenal were back at The Hawthorns for the first time since winning on the final day of last season to secure Champions League qualification.
They returned in the midst of another battle to reach Europe's elite club competition.
That perhaps contributed to a edgy start, in which Rosicky was forced to clear a Yacob header off the line. But if his intervention was vital in defence, it was equally telling in attack.
Gervinho collected Mikel Arteta's long ball forward, befuddling Gareth McAuley, before producing a strike that was intercepted by Rosicky with a thumping near-post header.
The breakthrough appeared to settle Arsenal's nerves and Ben Foster saved well with his legs to deny Gervinho, while Aaron Ramsey prodded wide when he should have found the net.
West Brom offered little in attack, though they had strong claims for a penalty when Laurent Koscielny brought down Yacob.
With the Baggies yet to come from behind at half-time to win a game this season, and Arsenal in possession of the division's best second-half record, a turnaround seemed unlikely.
The odds lengthened when Rosicky doubled his side's advantage, beating Foster at the second attempt having been set up by Ramsey.
Steve Clarke responded by introducing Romelu Lukaku and Markus Rosenberg, and immediately West Brom carried a greater threat.
Top scorer Lukaku tested Lukasz Fabianski with a deflected free-kick, before the Polish goalkeeper denied Chris Brunt from a tight angle.
Long then met a perfectly weighted pass over the top, drawing a clumsy foul from Mertesacker that earned the German a straight red card.
Morrison drilled his spot-kick through the legs of Fabianski to haul his side back into contention with half an hour remaining.
As West Brom pressed hard for an equaliser, Arsenal manager Arsene Wenger sent on defensive reinforcements in the form of Thomas Vermaelen, Kieran Gibbs and Francis Coquelin.
McAuley headed off target, Lukaku curled a glorious chance wide and Long lashed over the bar when well placed.
Arsenal's celebrations at full-time showed how much the result meant.
West Brom manager Steve Clarke:
"I thought we played well today. They scored in the first half with one of the very few chances they created. We had good control in the first half but didn't really create enough.
"We could have had a penalty for a challenge on Claudio Yacob on the edge of the box [by Laurent Koscielny]. On another day that was a penalty and would have changed the complexion of the afternoon.
"We were disappointed to lose the second goal at the start of the second half. It was crucial for us to get back in it and we gave away another soft goal, a bad goal to lose.
"At 2-0 it is difficult to chase the game. We made a couple of changes. Then the penalty and the red card does change the game and gives us the chance to get something from the game."
Arsenal manager Arsene Wenger:
"We know we have one target - to win our games. Then we don't have to look at Tottenham or Chelsea.
"If we lose our games, then you have to look at the results of the others. Our attitude is simple, we have to win the games.
"Can we finish fourth? I believe we will do it. We are conscious as well we have to give 100 per cent commitment in every game and it will be difficult and edgy to the end.
"We are ready for the fight and we always tell the players 'don't look at everyone else, just focus on ourselves'."
West Bromwich Albion
- 01 Foster
- 03 Olsson
- 06 Ridgewell Booked
- 23 McAuley
- 28 Jones Booked
- 05 Yacob
- 07 Morrison
- 11 Brunt
- 14 Thomas (Rosenberg - 62' )
- 17 Dorrans (Lukaku - 62' )
- 09 Long
- 13 Myhill
- 04 Popov
- 30 Tamas
- 43 Brown
- 08 Rosenberg
- 20 Lukaku
- 32 Fortune
- 21 Fabianski
- 03 Sagna
- 04 Mertesacker Dismissed
- 06 Koscielny Booked
- 17 Monreal
- 07 Rosicky Booked (Gibbs - 81' )
- 08 Arteta Booked
- 16 Ramsey Booked
- 19 Cazorla (Coquelin - 89' )
- 12 Giroud
- 27 Gervinho (Vermaelen - 73' )
- 24 Mannone
- 05 Vermaelen
- 25 Jenkinson
- 28 Gibbs
- 15 Oxlade-Chamberlain
- 22 Coquelin
- 09 Podolski
Live Text Commentary
Full Time The referee signals the end of the game.90:00 +4:51
Olivier Giroud produces a left-footed shot from the edge of the box and misses to the right of the goal.90:00 +3:57
The assistant referee flags for offside against Romelu Lukaku. Lukasz Fabianski takes the indirect free kick.90:00 +0:51
Shot by Claudio Yacob from outside the area goes high over the crossbar.88:18 Substitution
Substitution Francis Coquelin joins the action as a substitute, replacing Santi Cazorla.88:03
Shot from inside the area by Shane Long clears the bar.85:17
Bacary Sagna restarts play with the free kick.85:17 Booking
Booking The referee cautions Liam Ridgewell for unsporting behaviour.85:12
Free kick awarded for an unfair challenge on Santi Cazorla by Liam Ridgewell.83:22
Effort on goal by Romelu Lukaku from deep inside the penalty area misses to the right of the goal.82:14
Chris Brunt takes the free kick.82:14 Booking
Booking Booking for Mikel Arteta.82:07
Billy Jones fouled by Mikel Arteta, the ref awards a free kick.80:51 Substitution
Substitution Kieran Gibbs joins the action as a substitute, replacing Tomas Rosicky.79:25
Outswinging corner taken by Chris Brunt from the left by-line, Close range headed effort by Gareth McAuley misses to the right of the target.77:13
Thomas Vermaelen restarts play with the free kick.77:13 Booking
Booking Billy Jones goes into the referee's book for unsporting behaviour.77:08
Mikel Arteta fouled by Billy Jones, the ref awards a free kick.76:17
Free kick awarded for a foul by Shane Long on Nacho Monreal. Nacho Monreal restarts play with the free kick.75:13
Header from deep inside the area by Romelu Lukaku goes harmlessly over the crossbar.
The referee blows for offside. Free kick taken by Jonas Olsson.74:03
Shane Long is caught offside. Lukasz Fabianski restarts play with the free kick.72:18 Substitution
Substitution Thomas Vermaelen comes on in place of Yao Gervinho.71:36
Markus Rosenberg challenges Laurent Koscielny unfairly and gives away a free kick. Free kick taken by Lukasz Fabianski.70:32
Shane Long provided the assist for the goal.70:32 Goal scored
Goal! - James Morrison - West Brom 1 - 2 Arsenal Power penalty scored by James Morrison. West Brom 1-2 Arsenal.69:49 Dismissal
Dismissal The referee red cards Per Mertesacker for professional foul.69:42
Foul by Per Mertesacker on Shane Long, Penalty awarded.69:17
Unfair challenge on Mikel Arteta by James Morrison results in a free kick. Mikel Arteta takes the direct free kick.68:56
Olivier Giroud concedes a free kick for a foul on Gareth McAuley. Direct free kick taken by Gareth McAuley.66:52
Chris Brunt takes a shot. Save made by Lukasz Fabianski. Markus Rosenberg takes the inswinging corner, Shane Long produces a header from inside the six-yard box that clears the bar.66:28
Tomas Rosicky is caught offside. Free kick taken by Jonas Olsson.64:40
Romelu Lukaku fires a strike on goal direct from the free kick, save by Lukasz Fabianski.64:40 Booking
Booking Caution for Laurent Koscielny.64:36
Unfair challenge on Shane Long by Laurent Koscielny results in a free kick.62:52
Inswinging corner taken right-footed by Santi Cazorla from the left by-line to the near post, Shane Long makes a clearance.61:17 Substitution
Substitution Markus Rosenberg replaces Jerome Thomas.61:17 Substitution
Substitution (West Brom) makes a substitution, with Romelu Lukaku coming on for Graham Dorrans.61:04
Jerome Thomas has an effort at goal from outside the box which goes wide left of the target.60:28
Mikel Arteta challenges James Morrison unfairly and gives away a free kick. Direct free kick taken by James Morrison.59:02
Effort on goal by Santi Cazorla from just outside the penalty area goes harmlessly over the target.56:25
Corner taken by Graham Dorrans, Aaron Ramsey manages to make a clearance.51:56
Free kick awarded for an unfair challenge on Jonas Olsson by Olivier Giroud. Ben Foster takes the free kick.51:31
Chris Brunt takes a shot from 35 yards clearing the bar.49:51
Aaron Ramsey provided the assist for the goal.49:51 Goal scored
Goal! - Tomas Rosicky - West Brom 0 - 2 Arsenal Tomas Rosicky scores a goal from inside the penalty area to the bottom left corner of the goal. West Brom 0-2 Arsenal.49:42
Shot from 20 yards from Tomas Rosicky. Ben Foster makes a save.47:27
Bacary Sagna takes a shot. Outswinging corner taken by Santi Cazorla from the right by-line played to the near post, save by Ben Foster. Jonas Olsson manages to make a clearance.45:01
The referee starts the second half.45:00 +1:06 Half time
Half Time The half-time whistle blows.43:59
Corner taken by Chris Brunt from the right by-line to the near post, save by Lukasz Fabianski.42:42
Santi Cazorla takes the inswinging corner, Header from deep inside the area by Olivier Giroud goes over the bar.42:17
Shot from inside the six-yard box by Aaron Ramsey goes wide right of the target.40:29
Shot from just outside the box by James Morrison goes over the bar.37:33
Corner taken by Santi Cazorla played to the near post.36:06
Chris Brunt shoots direct from the free kick.36:06 Booking
Booking Tomas Rosicky is booked.36:00
Tomas Rosicky challenges James Morrison unfairly and gives away a free kick.32:51
Laurent Koscielny challenges James Morrison unfairly and gives away a free kick. Chris Brunt takes the free kick.30:15
Olivier Giroud fouled by Jonas Olsson, the ref awards a free kick. Mikel Arteta restarts play with the free kick.29:42
Unfair challenge on Liam Ridgewell by Olivier Giroud results in a free kick. Free kick taken by Jonas Olsson.28:00
Yao Gervinho takes a shot. Save by Ben Foster. Aaron Ramsey takes a shot. Save by Ben Foster.27:23
Yao Gervinho challenges Claudio Yacob unfairly and gives away a free kick. Direct free kick taken by Claudio Yacob.25:16
Graham Dorrans takes the free kick.25:16 Booking
Booking Aaron Ramsey booked.25:03
Aaron Ramsey gives away a free kick for an unfair challenge on Jerome Thomas.23:15
Tomas Rosicky concedes a free kick for a foul on Billy Jones. Chris Brunt produces a shot on goal direct from the free kick, save by Lukasz Fabianski.22:24
Olivier Giroud challenges Liam Ridgewell unfairly and gives away a free kick. Free kick taken by Liam Ridgewell.22:07
Free kick awarded for an unfair challenge on Claudio Yacob by Aaron Ramsey. Jonas Olsson restarts play with the free kick.19:51
Yao Gervinho provided the assist for the goal.19:51 Goal scored
Goal! - Tomas Rosicky - West Brom 0 - 1 Arsenal Tomas Rosicky finds the net with a headed goal from inside the six-yard box. West Brom 0-1 Arsenal.19:00
Liam Ridgewell fouled by Bacary Sagna, the ref awards a free kick. Direct free kick taken by Ben Foster.17:17
The assistant referee flags for offside against Shane Long. Laurent Koscielny restarts play with the free kick.16:24
Shane Long has an effort at goal from just inside the box that misses to the right of the goal.11:03
Chris Brunt takes a inswinging corner from the right by-line played to the near post, Claudio Yacob takes a shot. Blocked by Tomas Rosicky. Shot from deep inside the area by Claudio Yacob goes over the bar.10:22
Corner taken by Graham Dorrans played to the near post, Per Mertesacker makes a clearance.8:50
Shane Long is ruled offside. Laurent Koscielny restarts play with the free kick.7:31
Nacho Monreal has an effort from just inside the box that misses to the left of the target.4:26
The assistant referee flags for offside against Billy Jones. Free kick taken by Lukasz Fabianski.2:12
Free kick awarded for an unfair challenge on Tomas Rosicky by Claudio Yacob. Mikel Arteta restarts play with the free kick.0:47
The referee blows for offside against Shane Long. Per Mertesacker restarts play with the free kick.0:00
The match gets underway.
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