Olivier Giroud scored his first Premier League goal for Arsenal as the Gunners came from behind to beat West Ham.
West Ham took the lead against the run of play when Mohamed Diame beat Vito Mannone with a curling shot.
Giroud equalised before the break when he poked in Lukas Podolski's cross at the near post.
Kevin Nolan missed two chances for the hosts and was made to pay when Theo Walcott came off the bench to make it 2-1 with Santi Cazorla hitting a third.
Wenger praises 'convincing' win
Walcott, who replaced the disappointing Gervinho, helped the Gunners take advantage in the last half hour as West Ham tired.
But having been on top for large parts of the game, it was no more than Arsene Wenger's team deserved as they extended their unbeaten record against the Hammers to nine games and moved to fifth in the Premier League table.
Sam Allardyce's side had to defend stoutly throughout the game but they came up against a midfield again run by the impressive Cazorla.
And their disappointment in losing their first Premier League home game of the season was compounded by an injury to forward Ricardo Vaz Te, who went off with a suspected dislocated shoulder.
Walcott and Cazorla's late goals in the space of six minutes gave the scoreline added gloss as Andy Carroll caused concern in the visitors' defence on the striker's first start since suffering a hamstring injury.
Giroud hits the mark
Olivier Giroud scored his first Premier League goal after going 303 minutes without one
It was his 12th shot (15, inc. blocked) in the Premier League that he finally netted with
But the result was the perfect response to the Gunners' defeat by Chelsea last weekend and means that is the only league defeat of their season so far.
Carroll's value was also underlined when he spent much of the first 20 minutes bolstering the Hammers defence as Arsenal wasted a number of promising opportunities.
Giroud almost scored in the first two minutes when Jussi Jaaskelainen tipped his shot round the post and Carroll blocked the French striker's goal-bound effort later in the first half.
So when West Ham's goal came on 21 minutes it was something of a surprise. Diame was fed by George McCartney down the left and the Senegalese player skipped past Aaron Ramsey before curling a delightful finish into the far corner for his first Hammers goal.
Referee Phil Dowd booked the midfielder for his celebration and perhaps Diame was fortunate to stay on the field soon after when he clattered Mikel Arteta.
Arsenal punished us - Allardyce
Then, just as Carroll began to become more influential in the attacking half, Diame had his pocket picked in midfield leading to the equaliser.
The ball was swept to Podolski on the left and Giroud burst to the near post to tuck in the German's cross for a true poacher's goal.
Having got themselves back on level terms, Arsenal took time to warm to a similarly attacking theme as the first period.
By that stage, Carroll had almost made it 2-1 but his header from a long diagonal ball was just wide with Mannone beaten to the delivery, while Nolan wasted a great chance when clean through.
As Arsenal began to assert their authority on the game, Walcott latched onto Giroud's through ball just 16 minutes after coming on to score his fourth goal of the season with a precise near-post shot.
Another chance fell to Nolan, but he fired over from the edge of the penalty box, and that miss proved costly once Cazorla smashed in Arsenal's third from 20 yards to cap a superb individual performance.
The only worry for Arsenal was with left-back Kieran Gibbs, who left the field in the second half with what Wenger described afterwards as a "thigh problem".
Olivier Giroud takes a shot. Save by Jussi Jaaskelainen.
Aaron Ramsey takes a short corner.
Mark Noble fouled by Olivier Giroud, the ref awards a free kick. Direct free kick taken by Mark Noble.
Shot by Matthew Taylor. Vito Mannone makes a save.
Corner taken right-footed by Mark Noble, clearance by Per Mertesacker.
Andy Carroll gives away a free kick for an unfair challenge on Carl Jenkinson. Carl Jenkinson takes the free kick.
Theo Walcott restarts play with the free kick.
Booking Matthew Taylor receives a caution.
Matthew Taylor gives away a free kick for an unfair challenge on Mikel Arteta.
Substitution Laurent Koscielny is brought on as a substitute for Lukas Podolski.
Olivier Giroud has an effort from just inside the box that misses to the left of the goal.
Assist by Theo Walcott.
82:05 Goal scored
Goal! - Santi Cazorla - West Ham 1 - 3 Arsenal Santi Cazorla scores a goal from just outside the box to the top right corner of the goal. West Ham 1-3 Arsenal.
Substitution (West Ham) makes a substitution, with Carlton Cole coming on for Mohamed Diame.
Per Mertesacker takes a shot. Blocked by James Collins. Corner taken by Santi Cazorla, Olivier Giroud takes a shot. Jussi Jaaskelainen makes a save.
Corner taken right-footed by Santi Cazorla, clearance by Winston Reid.
Kevin Nolan produces a left-footed shot from inside the area that goes over the bar.
Free kick awarded for a foul by Matthew Taylor on Lukas Podolski. Clarindo Andre Santos takes the direct free kick.
Booking Theo Walcott shown a yellow card.
Assist on the goal came from Olivier Giroud.
76:09 Goal scored
Goal! - Theo Walcott - West Ham 1 - 2 Arsenal Theo Walcott scores a goal from the edge of the penalty area to the bottom right corner of the goal. West Ham 1-2 Arsenal.
Lukas Podolski takes a shot. Blocked by James Tomkins. Outswinging corner taken from the right by-line by Santi Cazorla, clearance made by Andy Carroll.
Santi Cazorla takes the inswinging corner, Winston Reid makes a clearance.
Corner taken by Santi Cazorla, George McCartney manages to make a clearance.
Inswinging corner taken right-footed by Santi Cazorla from the left by-line, clearance made by Andy Carroll.
Substitution James Tomkins comes on in place of Guy Demel.
Shot from 18 yards from Lukas Podolski. Save made by Jussi Jaaskelainen.
Santi Cazorla takes a shot. Blocked by James Collins.
Santi Cazorla has shot on goal from just outside the box which goes wide of the right-hand upright.
Andy Carroll has a headed effort at goal from close in which goes wide right of the goal.
Shot by Santi Cazorla. Olivier Giroud gets a block in. Shot from close in by Olivier Giroud misses to the left of the target.
Mohamed Diame fouled by Mikel Arteta, the ref awards a free kick. Matthew Taylor delivers the ball from the free kick left-footed from right wing.
Vito Mannone takes the free kick.
Substitution Matthew Taylor on for Ricardo Vaz Te.
Ricardo Vaz Te challenges Vito Mannone unfairly and gives away a free kick.
Substitution Yao Gervinho leaves the field to be replaced by Theo Walcott.
Effort on goal by Matthew Jarvis from deep inside the area goes harmlessly over the bar.
Inswinging corner taken by Santi Cazorla from the left by-line, Kevin Nolan manages to make a clearance.
Mikel Arteta takes the direct free kick.
Substitution Clarindo Andre Santos on for Kieran Gibbs.
Free kick awarded for an unfair challenge on Santi Cazorla by Kevin Nolan.
Kevin Nolan is flagged offside by the assistant referee. Free kick taken by Vito Mannone.
Corner taken by Mark Noble from the left by-line, clearance by Olivier Giroud.
Lukas Podolski fouled by Andy Carroll, the ref awards a free kick. Free kick taken by Lukas Podolski.
Corner taken right-footed by Mark Noble from the left by-line, Vito Mannone makes a save. Kevin Nolan gives away a free kick for an unfair challenge on Vito Mannone. Vito Mannone restarts play with the free kick.
The second half kicks off.
45:00 +2:30 Half time
Half Time The ref blows to signal half-time.
Free kick awarded for an unfair challenge on Guy Demel by Aaron Ramsey. Jussi Jaaskelainen takes the direct free kick.
Mark Noble delivers the ball, Effort from inside the six-yard box by Kevin Nolan goes wide right of the target.
45:00 +0:50 Booking
Booking Yao Gervinho goes into the referee's book for unsporting behaviour.
Foul by Yao Gervinho on Mark Noble, free kick awarded.
Aaron Ramsey takes a shot. Kevin Nolan gets a block in.
Corner taken right-footed by Santi Cazorla from the left by-line, Winston Reid manages to make a clearance.
Santi Cazorla takes the outswinging corner, Andy Carroll makes a clearance.
The assist for the goal came from Lukas Podolski.
40:20 Goal scored
Goal! - Olivier Giroud - West Ham 1 - 1 Arsenal Olivier Giroud finds the net with a goal from close range high into the middle of the goal. West Ham 1-1 Arsenal.
The referee gives a free kick against Mikel Arteta for handball. Free kick taken by James Collins.
Kieran Gibbs takes the direct free kick.
Booking Winston Reid receives a caution.
Foul by Winston Reid on Santi Cazorla, free kick awarded.
Close range headed effort by Per Mertesacker misses to the right of the target.
Corner taken by Santi Cazorla from the left by-line, clearance by Matthew Jarvis.
Andy Carroll concedes a free kick for a foul on Mikel Arteta. Per Mertesacker takes the direct free kick.
Corner taken right-footed by Mark Noble from the right by-line, Andy Carroll takes a shot. Save by Vito Mannone.
The assistant referee flags for offside against Yao Gervinho. Jussi Jaaskelainen restarts play with the free kick.
Unfair challenge on Per Mertesacker by Mohamed Diame results in a free kick. Vito Mannone takes the direct free kick.
Free kick awarded for a foul by Olivier Giroud on Kevin Nolan. Direct free kick taken by James Collins.
Foul by Mohamed Diame on Mikel Arteta, free kick awarded. Direct free kick taken by Carl Jenkinson.
Aaron Ramsey has an effort at goal from outside the penalty box missing to the wide right of the goal.
Booking Mohamed Diame receives a yellow card.
Assist by George McCartney.
20:17 Goal scored
Goal! - Mohamed Diame - West Ham 1 - 0 Arsenal Mohamed Diame fires in a goal from just inside the penalty area to the top right corner of the goal. West Ham 1-0 Arsenal.
Outswinging corner taken from the right by-line by Santi Cazorla, James Collins makes a clearance. Outswinging corner taken by Santi Cazorla. Shot by Olivier Giroud. Andy Carroll gets a block in. Corner taken right-footed by Santi Cazorla from the left by-line, clearance by Andy Carroll.
Thomas Vermaelen challenges Andy Carroll unfairly and gives away a free kick. Mark Noble delivers the ball from the free kick right-footed from left channel, clearance by Thomas Vermaelen.
Andy Carroll challenges Thomas Vermaelen unfairly and gives away a free kick. Direct free kick taken by Thomas Vermaelen.
Santi Cazorla takes a shot. Winston Reid gets a block in. Corner taken right-footed by Santi Cazorla, Andy Carroll makes a clearance.
Free kick awarded for an unfair challenge on Andy Carroll by Aaron Ramsey. James Collins takes the free kick.
Olivier Giroud takes a shot. Jussi Jaaskelainen makes a save. Corner taken right-footed by Santi Cazorla to the near post, clearance by Andy Carroll.
Lukas Podolski has shot on goal from just outside the penalty box which goes wide of the right-hand upright.
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