Theo Walcott scored the fastest Premier League goal of the season to sink QPR and send Arsenal into third place.
Walcott struck after 20 seconds, latching on to Mikel Arteta's deft pass and firing past Rob Green.
Arsenal dominated the early stages and went close to doubling their lead when Green clawed a low Walcott snap-shot on to his post.
Quick off the mark
Theo Walcott's strike after 20 seconds is Arsenal's fastest in the Premier League era and beats Robin van Persie's deflected goal after 32 seconds for Manchester United against West Ham as the fastest Premier League goal of the season. Van Persie scored what proved to be the winner against the Hammers at Old Trafford on 28 November.
Ledley King holds the record for the fastest goal in Premier League history (since 1992). He netted after 10 seconds in Tottenham's 3-3 draw at Bradford City on 9 December 2000.
QPR improved after the break but the closest they came to a reply was when Wojciech Szczesny denied Loic Remy.
Walcott's goal provided Arsene Wenger's side with an ideal start and was also the perfect riposte to Tottenham's win over Southampton earlier on Saturday. That had seen the Gunners temporarily drop to fifth place, a point behind Spurs and Chelsea who both have games in hand.
Whether Arsenal, who have been ever-presents in the Champions League for the past 15 seasons, finish in the top four this time remains to be seen but this victory, their sixth in their last eight games, at least gives them hope going into their last two games of the season.
It was by no means as straightforward a win as seemed likely when Walcott put them ahead, however.
Arsenal encountered little resistance as they advanced straight from kick-off and, following Armand Traore's poor header, Arteta got on the end of Tomas Rosicky's cross and slipped in Walcott to find a clinical finish.
Bottom side QPR initially offered little response and the Gunners continued to look dangerous whenever they ventured forward.
Walcott, who has now hit the 20-goal mark for the first time in a single season, went close to making it 2-0 before the half-hour mark when Green turned his low shot on to the post.
But the home side, whose relegation was confirmed last weekend, belatedly began to offer some resistance.
Andros Townsend was their biggest threat, repeatedly running at the Gunners defence and setting up shooting chances for Ji Sung Park and Bobby Zamora, both of which were wasted.
Arsenal remained on the back foot at the start of the second half. Townsend, on loan at Rangers from Arsenal's rivals Spurs, remained dangerous and his swerving shot forced a good save from Szczesny.
The Gunners found themselves in a scrap but responded with a spell where they dominated possession. They could not get behind QPR's defence, however, and it was the hosts who created the best late chances.
Remy also tested Szczesny after cutting in from the left and he repeated the trick with 10 minutes to go, this time with a curling shot that forced the Arsenal keeper into his best stop of the evening.
QPR manager Harry Redknapp:
"When you go 1-0 down to Arsenal in the first minute then you fear the worse, but I felt we played every bit as well as them.
"I felt we were always a threat and Andros Towsend was outstanding. I don't know where we'll get another Townsend from, he'll go back to Tottenham a better play.
"I'm looking forward to the challenge next season. I went to watch a (Championship) game today because we're going to be in that division next season."
Arsenal manager Arsene Wenger:
"We had a great start and surprised QPR. But then they came back strongly and showed they have no fear.
"I think they've got a good chance of coming back up to the Premier League. We're on a very strong run and want that to carry on until the end of the season.
"You can only win your own games and see what happens elsewhere. Football is unpredictable but for three months we've been in a position where we cannot afford to drop points."
Queens Park Rangers
- 01 Green
- 03 Traore (Fabio - 90' )
- 06 Hill
- 15 Onuoha
- 21 Ben-Haim
- 07 Park Ji-sung (Taarabt - 79' )
- 16 Jenas Booked
- 29 Townsend
- 40 M'bia (Derry - 46' Booked )
- 18 Remy
- 25 Zamora
- 26 Murphy
- 20 Fabio
- 04 Derry
- 10 Taarabt
- 14 Granero
- 12 Mackie
- 37 Bothroyd
- 01 Szczesny
- 03 Sagna
- 04 Mertesacker
- 06 Koscielny
- 17 Monreal Booked
- 07 Rosicky (Vermaelen - 90' )
- 08 Arteta
- 14 Walcott
- 16 Ramsey
- 19 Cazorla (Wilshere - 89' )
- 09 Podolski (Oxlade-Chamberlain - 85' )
- 24 Mannone
- 05 Vermaelen
- 25 Jenkinson
- 10 Wilshere
- 15 Oxlade-Chamberlain
- 22 Coquelin
- 27 Gervinho
Live Text Commentary
Full Time The referee signals the end of the game.90:00 +2:20 Substitution
Substitution Fabio Da Silva replaces Armand Traore.90:00 +0:37
Rob Green restarts play with the free kick.90:00 +0:37 Substitution
Substitution Thomas Vermaelen comes on in place of Tomas Rosicky.90:00 +0:37
Alex Oxlade-Chamberlain is flagged offside by the assistant referee.87:58 Substitution
Substitution Jack Wilshere on for Santi Cazorla.87:58
Effort on goal by Bobby Zamora from long range goes harmlessly over the bar.87:26
Shot by Aaron Ramsey from 20 yards. Save by Rob Green.84:09
Loic Remy is ruled offside. Free kick taken by Wojciech Szczesny.84:09 Substitution
Substitution Alex Oxlade-Chamberlain on for Lukas Podolski.82:54
Shot by Loic Remy. Fantastic save by Wojciech Szczesny. Andros Townsend takes a inswinging corner to the near post, Nacho Monreal manages to make a clearance.81:11
The referee blows for offside. Rob Green takes the free kick.80:00
Andros Townsend produces a cross.79:22
Shot from 18 yards from Aaron Ramsey. Blocked by Clint Hill.77:57
Direct free kick taken by Aaron Ramsey.77:57 Substitution
Substitution Ji-Sung Park goes off and Adel Taarabt comes on.77:57 Booking
Booking The referee cautions Jermaine Jenas for unsporting behaviour.77:47
Jermaine Jenas concedes a free kick for a foul on Tomas Rosicky.76:53
Loic Remy is ruled offside. Indirect free kick taken by Laurent Koscielny.76:07
Theo Walcott has a drilled shot. Save by Rob Green.
Inswinging corner taken by Santi Cazorla, Clint Hill makes a clearance.73:17
Free kick awarded for an unfair challenge on Santi Cazorla by Ji-Sung Park. Lukas Podolski produces a strike on goal direct from the free kick, Nedum Onuoha gets a block in.73:07
Shot by Lukas Podolski. Nedum Onuoha gets a block in.72:34
Free kick awarded for a foul by Nedum Onuoha on Aaron Ramsey. Free kick taken by Laurent Koscielny.71:32
Effort on goal by Theo Walcott from 25 yards. Clint Hill gets a block in.70:57
Santi Cazorla takes the outswinging corner, clearance made by Shaun Derry.70:25
Theo Walcott takes a shot. Rob Green makes a save. Inswinging corner taken right-footed by Theo Walcott from the left by-line to the near post, Clint Hill manages to make a clearance.67:41
Santi Cazorla has an effort at goal. Save by Rob Green.66:13
Corner taken by Santi Cazorla, Lukas Podolski gives away a free kick for an unfair challenge on Rob Green. Rob Green restarts play with the free kick.64:43
Laurent Koscielny takes a shot. Comfortable save by Rob Green.64:02
Free kick crossed by Theo Walcott, Tal Ben Haim manages to make a clearance.64:02 Booking
Booking The referee books Shaun Derry for unsporting behaviour.63:41
Shaun Derry challenges Tomas Rosicky unfairly and gives away a free kick.60:58
Andros Townsend takes a outswinging corner from the left by-line to the near post, Nacho Monreal makes a clearance.58:55
The free kick is swung in left-footed by Andros Townsend, clearance made by Per Mertesacker.58:55 Booking
Booking Nacho Monreal goes into the book.58:42
Free kick awarded for a foul by Nacho Monreal on Andros Townsend.57:24
Lukas Podolski is ruled offside. Rob Green takes the indirect free kick.55:52
Unfair challenge on Lukas Podolski by Nedum Onuoha results in a free kick. Lukas Podolski restarts play with the free kick.54:58
Shot from 20 yards from Loic Remy. Comfortable save by Wojciech Szczesny.53:27
Andros Townsend takes a shot. Save by Wojciech Szczesny. Shot by Jermaine Jenas. Blocked by Laurent Koscielny.49:57
Ji-Sung Park takes a shot. Wojciech Szczesny makes a comfortable save.47:10
Free kick awarded for an unfair challenge on Clint Hill by Lukas Podolski. Rob Green takes the direct free kick.45:46
Handball decision goes against Aaron Ramsey. The free kick is delivered right-footed by Jermaine Jenas from left channel, clearance made by Tomas Rosicky.45:01
The game restarts for the second half.45:01 Substitution
Substitution Shaun Derry replaces Stephane Mbia.45:00 +0:58 Half time
Half Time The referee calls an end to the first half.44:19
Loic Remy concedes a free kick for a foul on Nacho Monreal. Wojciech Szczesny restarts play with the free kick.41:30
Free kick awarded for a foul by Bacary Sagna on Ji-Sung Park. Direct strike on goal from the free kick comes in from Andros Townsend.40:53
Free kick awarded for a foul by Clint Hill on Theo Walcott. Tomas Rosicky restarts play with the free kick.40:05
Stephane Mbia takes a shot from long distance which goes wide of the right-hand post.38:11
Corner taken right-footed by Theo Walcott to the near post, comfortable save by Rob Green.37:10
Free kick awarded for a foul by Mikel Arteta on Loic Remy. Stephane Mbia takes the free kick.36:32
Drilled right-footed shot by Tal Ben Haim. Wojciech Szczesny makes a comfortable save.34:56
The offside flag is raised against Loic Remy. Wojciech Szczesny takes the indirect free kick.31:46
Handball decision goes against Lukas Podolski. Direct free kick taken by Rob Green.30:11
Ji-Sung Park takes a shot. Blocked by Laurent Koscielny. Inswinging corner taken left-footed by Andros Townsend from the right by-line, Wojciech Szczesny makes a save.28:13
The official flags Theo Walcott offside. Indirect free kick taken by Rob Green.27:33
Ji-Sung Park produces a right-footed shot from inside the area that clears the crossbar.25:48
Theo Walcott takes a shot. Save made by Rob Green.20:32
Effort from outside the box by Loic Remy goes wide right of the target.18:50
Short corner taken by Theo Walcott from the right by-line.18:12
Handball decision goes against Theo Walcott. Armand Traore takes the direct free kick.17:19
Andros Townsend takes a shot. Blocked by Laurent Koscielny. The offside flag is raised against Bobby Zamora. Indirect free kick taken by Wojciech Szczesny.16:07
Effort from 12 yards by Theo Walcott. Blocked by Clint Hill.14:25
Santi Cazorla takes a shot. Blocked by Clint Hill.11:02
Corner taken by Theo Walcott, Rob Green makes a comfortable save.9:57
Free kick awarded for an unfair challenge on Jermaine Jenas by Lukas Podolski. Armand Traore takes the free kick.8:39
The referee blows for offside. Indirect free kick taken by Wojciech Szczesny.8:20
Lukas Podolski is caught offside. Free kick taken by Clint Hill.1:29
Stephane Mbia concedes a free kick for a foul on Mikel Arteta. Laurent Koscielny takes the direct free kick.0:20
Assist on the goal came from Mikel Arteta.0:20 Goal scored
Goal! - Theo Walcott - QPR 0 - 1 Arsenal Theo Walcott fires in a goal from inside the area to the bottom left corner of the goal. QPR 0-1 Arsenal.0:00
The game kicks-off.
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