The Europa League semifinals will be Arsenal's first ever competitive meeting with Atletico Madrid. And yet the Gunners will be up against a familiar foe when they take on the Spanish side.

That's right, Arsenal fans' favourite villain Diego Costa could come back to haunt the club again. The former Chelsea striker has had some memorable battles against Arsene Wenger's side and will relish the chance to rattle the Gunners' back four once again.

That is, if he's fit to play. Costa limped off with a thigh injury during Thursday's quarterfinal against Sporting Lisbon, and Arsenal may well hope he doesn't recover in time for the April 26 semifinal at the Emirates.

Here's a look at Arsenal's top tussles with Costa in the past, showing why he could be the biggest threat to Arsenal's hopes of reaching the Europa League final in Lyon ...

Chelsea 2-0 Arsenal -- Premier League, Oct. 5, 2014

Costa's first game against Arsenal was more memorable for a dust-up between the two managers, with Arsene Wenger shoving Jose Mourinho in the chest as tempers flared on the sidelines at Stamford Bridge. But Costa delivered the bigger blow when he killed off the game by scoring Chelsea's second, beating Per Mertesacker and Laurent Koscielny to a perfect ball over the top from former Gunner Cesc Fabregas and coolly chipping the ball into the net. It wasn't the last time he'd prove a thorn in Arsenal's side.

Chelsea 2-0 Arsenal -- Premier League, Sept. 19, 2015

This was the game that turned Costa into arch villain No. 1 in the eyes of many Arsenal fans. He didn't score but had a decisive impact when he managed to get Gabriel Paulista sent off through a mix of theatrics and dirty tricks. Costa first got away with swiping Koscielny in the face and pushing the centre-back to the ground, then managed to rile up Gabriel to the extent that the Brazilian retaliated unwisely to get a second booking. Down to 10 men, Arsenal couldn't withstand Chelsea's pressure in the second half with Kurt Zouma scoring the opener in 53rd minute, before a late own-goal from Calum Chambers sealed the result. The fact that Costa was handed a three-game ban retrospectively, while Gabriel's suspension was overturned, did little to take away the sense of injustice.