Leading 1-0 thanks to Alexandre Lacazette's opener and with Atleti down to 10 men, it was looking like a good night's work for the 'Gunners', only for them to shoot themselves in the foot with just over 10 minutes to go.
Koscielny got caught under a long ball forward and failed to deal with it, allowing Griezmann, who had been quiet for most of the game, to steal in.
David Ospina flew off his line to make the initial save but as the ball rebounded back to the French international he made no mistake, slamming the ball into the roof of the unguarded net.
Check out the strike for yourself below:
April 26, 2018