Crystal Palace chairman Steve Parish has confirmed his club will appeal to the Court of Arbitration for Sport after being demoted from the Europa League.
Palace qualified for the Europa League with a shock FA Cup final win over Manchester City in May.
But Uefa, European football's governing body, ruled Palace should drop down to the Conference League over a conflict of interest involving the club's former director John Textor, who also part-owns French side Lyon.
Textor stepped away from Palace at the start of July, but the ownership issue relates to the end of last season when the south London team secured a maiden European appearance by winning the first major trophy in their history.
Uefa’s ruling would mean Nottingham Forest, who finished seventh in the Premier League, take Palace's place in the Europa League, but Parish has signalled his intent to contest the decision.
"We are still fighting," Parish told the The Rest is Football podcast. "There's an appeal process, so we go to CAS which is the court for arbitration and, you know, we're very hopeful. We think we've got great legal arguments.
"We don't think this is the right decision by any means. We know unequivocally that John didn't have decisive influence over the club.
"We know we proved that beyond all reasonable doubt because it's a fact."
Uefa rules say that no owner or co-owner can have a controlling interest in more than one club competing in the same European competition during the same season.
Palace's position throughout has been that Textor did not have a sufficiently controlling role for the club to fall foul of the regulations.
But the deadline for shareholders to divest their interest in a club, or in some other way to alter their ownership structure, in order to comply with the regulations was 1 March.