London - Outgoing Arsenal manager Arsene Wenger lamented a familiar defensive lapse as his side failed to cash in on a man advantage for over 80 minutes in a 1-1 draw with Atletico Madrid in the first leg of their Europa League semi-final on Thursday.
Antoine Griezmann's away goal eight minutes from time is a body blow to Wenger's hopes of bowing out after 22 years on a high in the final on May 16, and Arsenal's chances of playing Champions League football next season.
Sime Vrsaljko's early red card handed the Gunners the initiative, however, they were made to rue a host of missed chances before and after Alexandre Lacazette headed them in front on the hour mark.
"I feel we produced the performance we wanted to produce, but the result is not in line with the performance," said Wenger.
"We can only look at ourselves for tonight's result because 1-0 is a perfect result at home. It was up to us not to make a mistake...it is a story we have seen before."
Atletico coach Diego Simeone was also sent to the stands shortly after Vrsaljko's dismissal, but the Spaniards resisted manfully and Simeone hailed their resistance.
"You don't have any idea how hard it is to defend and defend and defend," said Simeone. "You have to have huge balls to defend for more than 80 minutes like that.
"These players of Atletico Madrid are heroes to resist like that."
Arsenal now need to become the first away team to score in 12 matches at Atletico's Wanda Metropolitano stadium next week to progress, and Simeone urged the home support to create an explosive atmosphere.
"Next week the stadium has to explode with positive energy," added the Argentine.
"We can play well or badly but you don't see this commitment everywhere...I have goosebumps thinking about next week already."
There was a highly-charged atmosphere for Wenger's penultimate home game in charge and the hosts were given plenty of encouragement early on, even when still up against Atletico's full complement.
Lacazette volleyed off the outside of the post and forced Jan Oblak into the first of a series of fine saves with a header from close range.
Vrsaljko had been booked within two minutes for bringing down Jack Wilshere.
And the Croatian left his side a man light after just 10 minutes when French referee Clement Turpin showed no leniency for another late challenge on Lacazette.
Moments later, Simeone was also dismissed by the officious referee for taking his protests too far when an Arsenal player wasn't booked for what he thought was a similar foul.
Atletico's excellent defensive record is what has carried them to five European semi-finals in seven seasons under Simeone.
The visitors battened down the hatches with 10 men, but were reliant on Oblak, who Wenger described as "one of the best goalkeepers in the world", to keep them in the tie.
"Of course you come out tonight with a bitter taste because we had the chances to be in the final tonight," added Wenger.
"The regret is we were not clinical enough."
Atletico retreated ever deeper towards their own goal after the break and were finally punished on the hour mark when Wilshere's deep cross found Lacazette rising above Lucas Hernandez to head in his seventh goal in seven games.
Arsenal could and should have added to their lead, but instead some comical defending cost them dearly when Atletico grabbed a vital away goal.
Griezmann outmuscled French international team-mate Laurent Koscielny and then benefited from a slip by Shkodran Mustafi after his initial effort had been saved by David Ospina to prod his 27th goal of the season into the roof of the net.
There was still time for Oblak to show why Griezmann isn't the only Atletico player wanted by Europe's elite with a spectacular one-handed save to turn Aaron Ramsey's header behind and keep Los Rojiblancos on course for a third European final in five seasons.