Josh James at Constant Vanden Stock Stadium
Arsenal claimed all three points thanks to a dramatic late turnaround against Anderlecht.
The Gunners looked to be falling to a disappointing - and potentially damaging - defeat until two goals in the final few minutes completed an unlikely win.
After a sterile first half, Andy Najar headed Anderlecht into a 71st-minute lead.
But with one minute left on the clock Kieran Gibbs smashed home the equaliser, and in injury time substitute Lukas Podolski grabbed the winner from close range.
SETTING THE SCENE
Arsène Wenger, celebrating his 65th birthday today, made three changes to the team which drew with Hull at the weekend.
Emiliano Martinez was named in the starting line up for his Champions League debut, replacing Wojciech Szczesny who was banned following his dismissal against Galatasaray. David Ospina is currently out with a thigh injury, so there was a place on the bench for 17-year-old academy goalkeeper Ryan Huddart.
Calum Chambers returned after his domestic ban to reclaim his place at right back while Aaron Ramsey was restored to the starting XI in place of Alex Oxlade-Chamberlain.
Anderlecht made four changes to the team that lost 3-0 at home to Borussia Dortmund on matchday two.
The first chance fell to Arsenal inside the opening three minutes. Alexis Sanchez, operating mainly on the right flank, cut the ball back to Santi Cazorla who had found a pocket of space inside the area, but he couldn't direct his first-time shot on target.
On 10 minutes Nacho Monreal was booked for bringing down Cyriac after the Ivorian striker outfoxed him with a swift turn 10 yards inside the Arsenal half.
A moment later Danny Welbeck's nimble footwork won him a free-kick just on the edge of the box when he was felled by Ibrahima Conte. Santi Cazorla struck the set piece straight into the wall however.
Anderlecht were looking dangerous on the break but Arsenal were carving out the better openings. Welbeck headed over from Alexis's right-wing cross, while Anderlecht keeper Silvio Proto punched clear under pressure when Cazorla's free-kick caused confusion in the box.
Then left back Frank Acheampong delivered a dangerous looking cross, but it evaded everyone in the box and drifted wide.
Arsenal were patiently trying to carve out chances – Alexis flashed a half-chance over the bar from close range – but neither keeper had to make a save in the first half.
Two minutes after the restart the ball fell to Conte in a good position inside the area, but his shot was deflected and bounced wide of the upright.
Alexis had a glancing header from close range pushed away by Proto and Ramsey sent his shot wide after being teed up by Alexis at the near post. Arsenal continued to dominate possession, but they were finding it hard to pick a way through the hosts' defence.
Anderlecht were springing forward when they got the opportunity. On 57 minutes the lively Conte fed Cyriac but his low shot from 25 yards was easily gathered by Martinez.
Alexis was the creator in chief and he threaded a ball through to Cazorla in the area on 64 minutes, but the Spaniard was denied well low by Proto. The ball found its way back to Alexis who blazed his shot well over from the edge of the box.
Then, with 19 minutes remaining, Anderlecht broke the deadlock. Dennis Praet stood the ball up to the far post and Najar rose highest to head into the bottom corner beyond Martinez from eight yards out.
The Belgians who nearly extended their lead. They counter-attacked in numbers to set up Anthony Vanden Borre in front of goal, but his sliced shot bounced off the bar. Martinez was rooted to the spot.
As the game entered the final 10 minutes Alexis bent his free-kick just wide after Cazorla was chopped down.
Anderlecht were growing in confidence. Matias Suarez nearly scored with his first touch after coming on. He was clean through on goal only to be let down by a heavy touch, enabling Martinez to snuff out the danger. Moments later Steven Defour saw his powerful strike saved by the young Argentine.
Just as the hosts looked like they would hold in for a famous win, Arsenal grabbed the equaliser. Chambers sent over a deep cross from the right and Gibbs arrived at the far post to smash a fine volley into the far corner.
It knocked the stuffing out of Anderlecht, and Arsenal would make them pay an even dearer price a minute into injury time. Podolski - on as a sub just five minutes earlier - was in the right place at the right time to power home Alexis's low drilled cross from close range.
It sparked jubilant celebrations from the travelling fans as Arsenal made it two wins in a row in Group D.
Referee: Carlos Velasco Carballo
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