Costa strike the difference as Wenger is denied his happy European ending
Atletico Madrid 1-0 Arsenal
Two European finals in 22 years. Say it fast and it sounds like almost nothing at all.
Arsene Wenger's hopes of bowing out with a Europa League final - to go with that 2000 Uefa Cup final against Galatasaray and the Champions League final in Paris against Barcelona in 2006 - were destroyed by Diego Costa. A familiar foe and a familiar story.
They dominated the game but couldn't make their possession count and when Costa scored his fourth goal against Arsenal in seven games they needed to become the first team to score past Jan Oblak at the Metropolitano Stadium since January and they were unable to.
Costa's goal came in the last attack that Arsenal had to deal with in the first half.
He has combined brilliantly with Antoine Griezmann since his return, although it has usually been the Frenchman scoring from Costa's assists. This time roles were reversed.
Griezmann, deep in the inside right channel, fizzed a diagonal pass to Costa who had muscled his way goalside of Hector Bellerin.
The Arsenal right-back tried to recover but Costa flicked him off and when David Ospina came out to meet him unconvincingly, making himself small instead of big, the Spain centre-forward smashed the ball past him to put Atletico Madrid 2-1 up on aggregate.
It was the second serious set-back that Arsenal had endured in the first 45 minutes.
Had Laurent Koscielny still been on the pitch he might have dealt better with the late Griezmann-Costa break but he only made it to minute 11.
In the first leg Atletico had lost Sime Vrsaljko and Diego Simeone in the first quarter of an hour, both sent off.
This time it was Arsenal weakened early, not by a card but by an injury that will probably rule its victim out of the World Cup.
Koscielny's right ankle collapsed beneath him as he began to sprint forward towards the halfway line. As he beat the turf in pain and fury Costa was the nearest to him and the first to tell his team-mates to kick the ball out of play.
Greizmann was next to arrive on the scene and his reaction said as much as Koscielny's. He tried to hurry up the stretcher-bearers who seemed to take an age to reach the Arsenal captain.
He has been struggling with an Achilles problem for over a year and it appeared to have given up on him at the worst moment possible - just before the World Cup and in a European semi-final.
Calum Chambers came on and the pattern of the game did not change. Jack Wilshere took the armband and got Arsenal passing in midfield with the 3,000-strong travelling support singing his name.
Arsenal had some joy down their left side where Thomas Partey was struggling at right-back and there were glimpses of Mesut Ozil's potential to unlock the defence that has only conceded four times at home all season. But for all the possession, clear-cut chances were few and far between. With a lot, Arsenal had done relatively little.
Atletico, in contrast, had done so much from almost nothing. One real chance and Costa had buried it to give them the half-time advantage.
Costa and Griezmann were a threat again at the start of the second half when the French forward raced away with Costa alongside him waiting for the pass.
Before it could come Nacho Monreal brought Griezmann down and joined Wilshere in the book.
Ozil then had the chance to bring Arsenal level on the night when he skipped away from Partey. The situation demanded that he took responsibility but instead of shooting he drilled the ball across the face of the goal in Alexandre Lacazette's vicinity but not close enough for him to finish.
Partey was struggling and Ozil got away from him again but once more the cross found no takers.
Granit Xhaka then shot from distance and Oblak had to get down well to push the ball out for a corner.
Henrikh Mkhitaryan came on for Wilshere and Fernando Torres replaced the tired - and by now booked - Costa with seven minutes left.
He had done his worst, ruining Wenger's happy ending.
Independent News Service