Arsene Wenger celebrated his 65th birthday with a vital Champions League win as Arsenal scored twice in the final two minutes to beat Anderlecht.
After a dire first half, the Belgian champions looked set to ruin Wenger’s day when Honduras winger Andy Najar headed in Dennis Praet’s cross.
But left-back Kieran Gibbs’s volley at the far post brought the Gunners level.
The Gunners’ remarkable fightback leaves them with six points at the halfway stage of Group D, with German side Borussia Dortmund leading the way with a perfect record of three wins.
Anderlecht’s late capitulation – which means they have not won in their last 11 Champions League ties – leaves them five points adrift of Wenger’s team ahead of next month’s return fixture at Emirates Stadium.
And Lukas Podolski smashed in the winner from close range as Arsenal maintained their grip on second place.
Arsenal knew that victories in their back-to-back matches against the Belgians would put them on the verge of the Champions League knockout phase for the 12th consecutive season.
But they looked to be facing an uphill task to reach the last 16 after Najar’s goal moved the home side close to their first win against English opposition since beating Manchester United in October 2000.
And the Gunners were fortunate not to fall further behind as a young Anderlecht side threatened to add to their tally.
Ex-Portsmouth defender Anthony Vanden Borre scuffed against the Arsenal post before goalscorer Najar smashed the rebound into the side-netting.
Wenger was forced into giving third-choice keeper Emiliano Martinez his Champions League debut in the absence of Wojciech Szczesny (suspension) and David Ospina (injury).
But the Argentine was barely called into action until the closing stages when he twice stopped Anderlecht doubling their lead.
Chile winger Alexis Sanchez provided Arsenal’s greatest threat in the first half, when neither side managed a shot on target, and continued to pose problems after the break with his pace and movement.
The £35m summer signing from Barcelona escaped his marker to meet Santi Cazorla’s curling free-kick with a flick which home keeper Silvio Proto pushed clear with a reaction save.