Antoine Griezmann's late goal punished Arsene Wenger's Arsenal in the last four of the Europa League on Thursday night, as 10-man Atletico Madrid salvaged a 1-1 draw in the first leg of the tie between the two teams.
It was Wenger's 107th - and final - European home game as Arsenal manager, and while his players gave their all and thoroughly deserved victory, a defensive lapse in the final ten minutes means Arsenal now face an uphill task of reaching the final of the competition.
It was his side that started the brighter, as the Gunners could have scored twice in the opening minutes. Alexandre Lacazette was denied on both occasions, first by the post with a volley and the second by an acrobatic save from Jan Oblak, beating away his header.
Atletico's poor start was soon made worse when their full-back, Sime Vrsaljko, was sent-off inside ten minutes, after two mistimed tackles both resulted in yellow cards. Soon after the French referee, Clement Turpin, turned his attentions to the Atletico Madrid coach, Diego Simeone, dismissing him too, after a barrage of gesticulations from the technical area.
Arsenal were flying and continued to create chances, the best of which falling to Danny Welbeck. The forward was through on goal with only Oblak to beat, but was denied by some more smart goalkeeping, this time deflecting the ball past the post with his outstretched leg.
Atletico started to bare their teeth toward the end of the half and David Ospina had to be alert to prevent Antoine Griezmann scoring his 27th goal of the season. A reminder to Arsenal, of the threat the Spanish side pose and the need to take most of the opportunity presented.
It was 0-0 at the break.
It looked as though it was going to be frustrating second half for the Gunners. Atletico reverted to type, pragmatic and resolute, defending deep with all ten men behind the ball. But their resolve was dented when, on the hour, Jack Wilshere hung a cross deep into the box and Lacazette rose first and highest above his markers, to head the ball past the stubborn Oblack.
But it was Atletico who scored the next goal. A hopeful long ball forward was chased again by the relentless Griezmann, who this time got his reward - shaking off Laurent Koscielny to the through ball and lifting into the back of the net over the hapless Shkodran Mustafi at the second attempt.
1-1, and a crucial away goal for Atletico. Arsenal will be left wondering what could have been.