Adrian Mutu has been ordered to pay Chelsea £14.3million in compensation after losing his final appeal over his sacking in the Swiss Federal Court.
Chelsea terminated Mutu's contract after he failed a drug test in 2004 even though he still had nearly four years left on the deal.
Mutu moved on to Italy and rebuilt his career at Juventus and Fiorentina.
Chelsea claimed the Romania international breached his contract and they were awarded damages by Fifa and the verdict was upheld by Court of Arbitration for Sport.
Mutu took his final appeal to the Swiss Federal Court, but they have also kicked out Mutu's appeal and he will forced to pay the full £14.3million sum to Chelsea.
"It reached the conclusion that this was not the case and the Romanian footballer's appeal was unfounded," the court said in a statement.
Mutu is currently suspended for nine months after twice testing positive for the banned stimulant sibutramine while playing for Fiorentina in January.