Antoine Griezmann gave Atletico Madrid the advantage over Arsenal after the Gunners wasted a glorious opportunity to take charge of their Europa League semi-final.
Madrid lost their cool at the Emirates as manager Diego Simeone, no stranger to a touchline tantrum, and defender Sime Vrsaljko were both sent off 10 minutes into this first-leg tie.
Arsenal eventually got their noses in front and looked to be taking a narrow lead to Spain next week until Griezmann punished some poor defending to put Madrid in the driving seat.
Alexandre Lacazette led the Arsenal frontline on his own in the absence of the ineligible Pierre-Emerick Aubameyang but found Atletico goalkeeper Jan Oblak in inspired form.
The former Lyon striker tried time and time again to find a way through and was supported well by Danny Welbeck and Mesut Ozil in attack.
The early flashpoint which led to Vrsaljko receiving his marching orders for two silly early bookings looked certain to be crucial with 80 minutes left to play.
However, the visitors finished the first half strongly and the supremely talented Antoine Griezmann forced a save from David Ospina to remind Wenger of the threat they posed.
Arsenal supporters have never been shy in voicing their displeasure on frustrating European nights but they showed patience here as their team looked to pick the Madrid lock.
That patience was rewarded shortly after the restart when Lacazette, who put in one of his best performances in a red and white shirt, headed home powerfully for the opening goal.
Simeone watched on liked a caged lion from the back row of the director’s box, refusing to take his seat as he prowled around searching for a solution.
He wasn’t short of options on the bench with Diego Costa, not yet fully fit after injury, and legendary ex-Liverpool and Chelsea striker Fernando Torres on standby.
But it was the man the Gunners who had so feared leading up to this match, Griezmann, who proved his worth to level the game.
Laurent Koscielny made a real mess of what appeared to be a simple defensive clearance and the Atletico superstar took full advantage and fired into the roof of the net.
Aaron Ramsey thought he had restored the lead moments later but yet again Oblak was equal to the effort and produced a stunning fingertip save to deny the Welshman.
♂️ Laurent Koscielny kicks the ball against his own face.
@AntoGriezmann scores a crucial away goal….
♂️ Pulls out @FortniteGame ‘Take The L’ celebration.
— SPORF (@Sporf) April 26, 2018
Wenger got to his feet and showed his frustration on the night of his final home European tie in charge of Arsenal before he heads for pastures new in the summer.
This will not be the way he wanted to sign off from continental football at the Emirates and now needs a massive performance from his team in the return leg to reach the final.
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Failure in the second leg will effectively end Arsenal’s season and perhaps see some of the frustration that had dissipated suddenly resurface as Wenger’s goodbye begins.