Israel Adesanya failed in his bid to become a two-weight world champion after he was outpointed by Jan Blachowicz.
Middleweight champion Adesanya was bidding to become the fifth fighter to hold two UFC titles simultaneously after Conor McGregor, Daniel Cormier, Henry Cejudo and Amanda Nunes.
But he struggled with the step up in weight and was dominated in the last two rounds when Blachowicz took the fight to the canvas and was beaten for the first time in mixed martial arts.
The Pole had won the the light-heavyweight title last September when he stopped Dominick Reyes after Jon Jones had vacated.
And he was handed a resounding win by the judges who scored the bout 49-46, 49-45, 49-45.
The winner, who named veteran Glover Teixeira as his preferred opponent for the second defence of his belt, said: "I thought that he would be a little bit faster, but he don't hit so hard.
"He was slower, but he hit harder, this was something I don't expect."
Adesanya added: "It didn't exactly go the way I wanted it to go but I dared to be great.
"The critics are the ones on the sidelines, but I'm the one putting it on the line."
In the first of three world title fights, Aljamain Sterling was crowned the new bantamweight champion after Petr Yan was disqualified for landing an illegal knee.
Yan was ahead on two of the three judges' scorecards before landing the shot which left Sterling writhing on the canvas.
He was ruled unable to carry on by the doctor and referee Mark Smith awarded him the fight - and the title - in bizarre fashion.
“That's not the way I wanted to win; that’s not the way I envisioned this," the new champion said.
"I was trying to continue even being all f***** up like that. I was in bad shape, and it would've just been ego taking over to take further punishment."
