Anderlecht produced a stunning fightback last night to prevent Arsenal securing their place in the last 16 of the Champions League, drawing 3-3 after trailing 3-0 in the 58th minute.
Substitute Aleksandar Mitrovic's last-minute header earned the Belgians a point in a thrilling Group D clash that kept alive their slender hopes of qualifying for the knockout round.
After their smash-and-grab raid in Brussels a fortnight ago when Arsenal scored twice late on for a fortuitous three points, the Gunners were cruising as goals by Mikel Arteta (penalty), Alexis Sanchez and Alex Oxlade-Chamberlain put them 3-0 up.
However, Anthony Vanden Borre's double - one a penalty - gave Anderlecht hope and Mitrovic completed a remarkable comeback. Arsenal have seven points, five behind Borussia Dortmund, with Anderlecht on two and Galatasaray on one.
Arsenal were guilty of conceding possession in sloppy fashion and Dennis Praet, who was on the books of the Londoners as a teenager, nearly scored with a shot that spun wide after a hefty deflection off Per Mertesacker.
The hosts were playing a dangerous game and Anderlecht looked more than capable of capitalising with Sacha Kljestan forcing a sharp save from Wojciech Szczesny.
Arsenal's opener then came out of the blue.
Danny Welbeck tussled with Chancel Mbemba in the area and when he went crashing to the ground, referee Clement Turpin pointed to the spot.
Arteta coolly dispatched the penalty to bring up Arsenal's 500th goal in the Emirates Stadium. A few minutes later Chilean marksman Sanchez grabbed his 10th goal since joining from Barcelona in the close season, lashing a ferocious right-foot drive past Silvio Proto after his initial free kick hit the wall and rebounded back to him.
When Oxlade-Chamberlain went through to slide in Arsenal's third goal it appeared to be game over - but Anderlecht were not finished.
Three minutes later a suspiciously offside-looking Vanden Borre converted from close range and the bearded defender gave the visitors real hope when he slotted home a 73rd-minute penalty.
Anderlecht levelled it on 90 minutes when Andy Najar's cross was glanced in by Mitrovic to send the visiting fans wild with delight.