Burnley have confirmed that one of their fans was stabbed in the leg and four more were injured ahead of Thursday's Europa League clash with Olympiacos in Athens.

The Clarets saw their hopes of reaching the group stages of the competition suffer a major setback when they were beaten 3-1 at the George Karaiskakis Stadium.

However, matters on the field were overshadowed by reports of unrest between supporters before the game, and the club have also confirmed that 22 fans were detained by police before the match due to drunkenness.

"Burnley Football Club has praised the behaviour of the travelling support who followed the Clarets to Athens. Just over 900 supporters were inside the away end of the George Karaiskakis Stadium for Burnley's Europa League tie at Olympiacos," read a statement on the club's official website.

"The vast majority were once again impeccably behaved with the coaching operation to transport supporters to the ground put in place by the club again a great success, as it was in the previous round in Istanbul. However, five of our supporters were unfortunately injured – including a person who received a stab wound to the leg – and received medical attention at the stadium.

"Those injured all travelled independently to the stadium, outside the organised travel operation. Burnley Football Club is working closely with Olympiacos and the local Greek police to investigate these incidents.

"A group of 22 supporters were detained by police ahead of the game for offences relating to drunkenness, in breach of Greek legislation. They were detained, rather than arrested, and released later on Thursday night without charge."

Burnley take on Fulham at Craven Cottage on Sunday before welcoming Olympiacos to Turf Moor for the return leg next Thursday.