Antoine Griezmann punished Arsenal's lax defence late on as 10-man Atletico Madrid salvaged a draw from the Europa League semi-final first leg at Emirates Stadium.
The visitors were on the back foot for almost the entire game on Thursday after defender Sime Vrsaljko was dismissed for two yellow cards in the first 10 minutes, according to a BBC report.
With Atletico's furious manager Diego Simeone sent to the stands shortly afterwards, the Spanish side survived unscathed to half-time, with Alexandre Lacazette clipping the post with a half-volley the hosts' best chance.
Lacazette nodded in Jack Wilshere's cross just after the hour to apparently edge the Gunners closer to a Europa League final send-off for outgoing manager Arsene Wenger.
But with eight minutes remaining, Griezmann latched on to a long ball forward, shrugged off Laurent Koscielny and stabbed into the net at the second attempt for an away goal to swing the tie Atletico's way going into the return leg in Madrid next Thursday.
Arsenal's fans were left ruing a familiar combination of wasteful finishing and costly lapses in concentration as the teams departed to a muted response in Wenger's final home European game.
Their team now must breach an Atletico defence that has conceded just four times at home in La Liga this season to have any hope of extending Wenger's 22-season spell in charge to the final on 16 May.
