Tyson Fury suffered a split-decision points defeat to Oleksandr Usyk on a dramatic night in Saudi Arabia as the Ukrainian became boxing's first four-belt undisputed heavyweight champion.
On a grand stage and on a legacy-defining night, Fury began well but was given a standing 10 count and saved by the bell after an Usyk onslaught in the ninth round.
The scorecards gave 115-112 and 114-113 decisions in favour of Usyk, with a third judge scoring it 114-113 to Fury.
It meant Fury, 35, lost for the first time in a 16-year professional career. He will get an immediate opportunity for revenge with a rematch planned for later this year.
"I believe he won a few of the rounds, but I won the majority," a defiant Fury said in the ring.
"It was one of the daftest decisions in boxing. I'll be back."
Usyk takes the WBC belt from Fury, to add to his WBA, WBO and IBF collection.
The 37-year-old remains unbeaten and is the first boxer in almost 25 years to stand tall as the sport's sole heavyweight world champion.
"Thank you so much to my team. It's a big opportunity for my family, for me, for my country. It's a great time, it's a great day," Usyk said.
"Yes, of course. I am ready for a rematch."