Tyson Fury insisted Oleksandr Usyk received an early Christmas gift from the judges after the Ukrainian won their heavyweight championship rematch on Saturday night.
The "Gypsy King," who was non-committal about his future, maintained that he had won the fight, which was scored 116-112 by all three officials in a unanimous decision.
The 36-year-old Fury, unbeaten until he first met Usyk in their four-belt unification fight in May, departs Riyadh's Kingdom Arena with two defeats on his record.
"Listen, it is what it is. I'm not going to cry over spilt milk; it's happened now," said Fury.
"I know boxing, I've been in it all my life—you can't change decisions. But I feel a little bit hard done by, actually a lot."
He added: "There was a little bit of Christmas spirit in there. He got a little Christmas gift."
Asked whether the public would see him fight again, Fury said: "You might do, you might not do. Who knows?"
Promoter Frank Warren also claimed victory for Fury, calling the decision "nuts."
He said the boxer, who needed a victory to trigger a trilogy fight, would need time to decide whether he will retire or return to the ring.
"That's up to him. I mean, it's just after a fight. Obviously, emotions are running high. We'll see," Warren said.
"It is what it is, and we'll have to see what happens in the future for Tyson. He'll make up his mind."