Theo Walcott's deflected late winner settled a pulsating encounter and sent Arsenal into the FA Cup fifth round at the expense of battling Brighton.
Gus Poyet's Championship side demonstrated exactly why they are play-off contenders as they pushed Arsenal every inch of the way before finally being beaten by substitute Walcott's strike five minutes from time.
Arsenal led twice through Olivier Giroud but in a thunderous atmosphere Brighton bounced back and looked to have secured at least a replay with goals from Ashley Barnes and £2m Argentine striker Leonardo Ulloa on his debut.
- Olivier Giroud has scored six goals in his last eight games (in all competitions) for Arsenal, including four in his last two.
Arsene Wenger sent on Walcott and Jack Wilshere in the second half to give Arsenal extra thrust and control.
And it was Walcott who answered his manager's call with a volley from the edge of the area after Brighton goalkeeper Casper Ankergren punched a corner out to the edge of the area.
This was the toughest of examinations for Arsenal - who are seeking their first trophy in eight years - and Wenger's delight at the final whistle was clear evidence of his relief and pleasure at negotiating it safely.
Brighton celebrate the 30th anniversary of reaching the FA Cup final against Manchester United - which they lost after a replay - this year and the old competition certainly stirred the emotions as the stadium crackled with noise and fervour throughout.
- Arsenal are unbeaten in 34 games against lower ranked sides in the FA Cup (since 0-1 defeat at Sheffield United in 1996).
Arsenal's visit drew a record crowd to The Amex - but they did not see Wilshere, Walcott and Santi Cazorla from the start as they were left on the bench.
Brighton have proved in the past they are undaunted by visitors from the Premier League. And so it proved again as they created the first clear opening, only for Barnes to miscue his volley and allow Wojciech Szczesny to save.
It was punished instantly as Arsenal swept to the other end to take the lead after 16 minutes, Giroud measuring a perfect left-foot finish high past Ankergren from 20 yards.
To Brighton's credit, they were not knocked out of their stride by the goal and applied pressure to Arsenal's struggling left-back Andre Santos as he battled to contain the lively Will Buckley.
Brighton, who had replaced injured captain Gordon Greer with Gary Dicker, drew level after 33 minutes as Barnes made amends for his earlier miss by beating Szczesny to David Lopez's cross to head in.
It was no more than they deserved, although they suffered another injury blow as the influential Buckley was replaced by Kazenga LuaLua at the start of the second half.
Arsenal opened with greater intent after the restart, with Lukas Podolski striking the bar from a free-kick, but it proved to be a temporary reprieve as the dangerous Giroud showed held off Adam El-Abd to sweep a finish past Ankergren from close range after 56 minutes.
In a thrilling game, Brighton once more showed their strength of character to draw level six minutes later. Arsenal's slack defending left manager Wenger infuriated on the sidelines as Ulloa stooped to send a diving header past Szczesny from Barnes's cross.
Wenger decided it was time to send on Wilshere and Walcott for Alex Oxlade-Chamberlain and Tomas Rosicky but it was Giroud who remained the danger man. He had already forced an important block from Ankergren then volleyed into the ground and just over as the game entered the final phase.
The decisive moment came when Ankergren's punch landed at the feet of Walcott on the edge of the area and his volley glanced off El-Abd into the net in front of Arsenal's ecstatic travelling support.
Live Text Commentary
Full Time The match has reached full-time.90:00 +3:33
Theo Walcott decides to take a short corner.90:00 +2:15
Kieran Gibbs concedes a free kick for a foul on Liam Bridcutt. Direct free kick taken by Inigo Calderon.89:48
Shot from close in by Craig Mackail-Smith misses to the left of the target.87:59
Corner taken left-footed by Jack Wilshere from the right by-line, Laurent Koscielny has shot on goal from just outside the area which goes wide of the right-hand upright.87:28
Short corner taken by Jack Wilshere from the right by-line.87:19
Theo Walcott takes a shot. Casper Ankergren makes a save.84:25 Goal scored
Goal! - Theo Walcott - Brighton 2 - 3 Arsenal Theo Walcott gets on the score sheet with a goal from just outside the box to the bottom right corner of the goal. Brighton 2-3 Arsenal.83:54
Corner from the right by-line taken by Jack Wilshere, save by Casper Ankergren.82:31
Aaron Ramsey concedes a free kick for a foul on Kazenga LuaLua. Direct free kick taken by Wayne Bridge.81:23
Olivier Giroud produces a left-footed shot from inside the area that clears the crossbar.77:47 Substitution
Substitution (Arsenal) makes a substitution, with Kieran Gibbs coming on for Clarindo Andre Santos.76:43
The referee blows for offside against Ashley Barnes. Per Mertesacker takes the indirect free kick.74:30
Corner taken by Jack Wilshere from the right by-line played to the near post, Craig Mackail-Smith makes a clearance.74:07
Jack Wilshere takes a inswinging corner from the right by-line played to the near post, clearance by Craig Mackail-Smith.72:18
Direct effort from the free kick comes in from Olivier Giroud.72:18 Substitution
Substitution Craig Mackail-Smith on for Jose Ulloa.72:18
Ashley Barnes gives away a free kick for an unfair challenge on Laurent Koscielny.71:36
Outswinging corner taken by Theo Walcott, Ashley Barnes manages to make a clearance.67:42
Direct free kick taken by Wayne Bridge.
Substitution Jack Wilshere on for Tomas Rosicky.67:42 Substitution
Substitution Theo Walcott is brought on as a substitute for Alex Oxlade-Chamberlain.67:42
Foul by Carl Jenkinson on Kazenga LuaLua, free kick awarded.65:39
Free kick taken by Moreno David Lopez.65:39 Booking
Booking Aaron Ramsey is cautioned by the ref for unsporting behaviour.65:34
Kazenga LuaLua fouled by Aaron Ramsey, the ref awards a free kick.62:55
Alex Oxlade-Chamberlain takes the inswinging corner, clearance by Adam El-Abd.61:22
The assist for the goal came from Ashley Barnes.61:22 Goal scored
Goal! - Jose Ulloa - Brighton 2 - 2 Arsenal Jose Ulloa finds the net with a headed goal from inside the area. Brighton 2-2 Arsenal.61:20
The ball is crossed by Ashley Barnes,59:38
Olivier Giroud takes a shot. Save by Casper Ankergren.58:06
Kazenga LuaLua fouled by Aaron Ramsey, the ref awards a free kick. Casper Ankergren takes the direct free kick.56:31 Booking
Booking Caution for Olivier Giroud.55:33
Vassiriki Diaby provided the assist for the goal.55:33 Goal scored
Goal! - Olivier Giroud - Brighton 1 - 2 Arsenal Olivier Giroud finds the net with a goal from inside the six-yard box low into the middle of the goal. Brighton 1-2 Arsenal.53:46
Shot from just outside the box by Jose Ulloa goes over the bar.53:01
Corner taken by Alex Oxlade-Chamberlain from the right by-line played to the near post, Liam Bridcutt manages to make a clearance.52:23
Adam El-Abd concedes a free kick for a foul on Alex Oxlade-Chamberlain. Shot comes in from Lukas Podolski from the free kick,50:35
Carl Jenkinson takes a shot. Save by Casper Ankergren.47:49
Vassiriki Diaby gives away a free kick for an unfair challenge on Jose Ulloa. Inigo Calderon takes the direct free kick.45:01
The referee gets the second half underway.45:01 Substitution
Substitution Will Buckley goes off and Kazenga LuaLua comes on.45:00 +3:40 Half time
Half Time The ref blows to end the first period.45:00 +3:27
Tomas Rosicky has an effort at goal from outside the penalty box which goes wide left of the goal.45:00 +2:21
Free kick awarded for an unfair challenge on Laurent Koscielny by Jose Ulloa. Wojciech Szczesny takes the direct free kick.45:00 +1:01
Clarindo Andre Santos produces a left-footed shot from long range that goes over the bar.44:37
Corner taken right-footed by Alex Oxlade-Chamberlain from the left by-line to the near post, Gary Dicker manages to make a clearance.42:43
Foul by Olivier Giroud on Ashley Barnes, free kick awarded. Adam El-Abd restarts play with the free kick.41:12
Tomas Rosicky fouled by Ashley Barnes, the ref awards a free kick. Clarindo Andre Santos takes the direct free kick.40:18
Vassiriki Diaby is penalised for handball and concedes a free kick. Casper Ankergren restarts play with the free kick.38:35
Corner taken by Alex Oxlade-Chamberlain from the right by-line to the near post, clearance made by Jose Ulloa.34:06
Alex Oxlade-Chamberlain takes the free kick.34:06 Substitution
Substitution Gary Dicker joins the action as a substitute, replacing Gordon Greer.34:06
Free kick awarded for an unfair challenge on Per Mertesacker by Jose Ulloa.32:17
Assist by Moreno David Lopez.32:17 Goal scored
Goal! - Ashley Barnes - Brighton 1 - 1 Arsenal Ashley Barnes grabs a headed goal from close range. Brighton 1-1 Arsenal.31:55
Will Buckley takes a short corner, The ball is delivered by Moreno David Lopez,29:55
The offside flag is raised against Jose Ulloa. Wojciech Szczesny takes the indirect free kick.29:22
Free kick awarded for a foul by Aaron Ramsey on Ashley Barnes. Direct free kick taken by Liam Bridcutt.28:10
Moreno David Lopez challenges Vassiriki Diaby unfairly and gives away a free kick. Direct free kick taken by Aaron Ramsey.27:11
Inswinging corner taken by Alex Oxlade-Chamberlain, save by Casper Ankergren.25:53
Corner taken right-footed by Alex Oxlade-Chamberlain from the left by-line to the near post, Jose Ulloa makes a clearance.24:32
Foul by Dean Hammond on Tomas Rosicky, free kick awarded. Carl Jenkinson restarts play with the free kick.23:06
Lukas Podolski gives away a free kick for an unfair challenge on Liam Bridcutt. Liam Bridcutt takes the free kick.22:40
Inigo Calderon produces a cross.18:00
Inswinging corner taken right-footed by Alex Oxlade-Chamberlain, Adam El-Abd manages to make a clearance.15:31
Assist by Lukas Podolski.15:31 Goal scored
Goal! - Olivier Giroud - Brighton 0 - 1 Arsenal A goal is scored by Olivier Giroud from just outside the penalty area to the top left corner of the goal. Brighton 0-1 Arsenal.15:08
Moreno David Lopez takes a short corner.14:46
Ashley Barnes takes a shot. Save by Wojciech Szczesny.11:16
Aaron Ramsey takes the free kick.11:16 Booking
Booking Moreno David Lopez receives a yellow card.11:05
Moreno David Lopez challenges Tomas Rosicky unfairly and gives away a free kick.6:10
Inswinging corner taken right-footed by Alex Oxlade-Chamberlain played to the near post, Jose Ulloa manages to make a clearance.4:57
The assistant referee flags for offside against Ashley Barnes. Indirect free kick taken by Wojciech Szczesny.2:44
Handball decision goes against Clarindo Andre Santos. Gordon Greer takes the free kick.2:00
Unfair challenge on Wayne Bridge by Alex Oxlade-Chamberlain results in a free kick. Wayne Bridge restarts play with the free kick.0:37
Dean Hammond challenges Clarindo Andre Santos unfairly and gives away a free kick. Free kick taken by Clarindo Andre Santos.0:00
The ref blows the whistle to start the match.
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