Sean Strickland stunned Israel Adesanya to win the middleweight title at UFC 293 in Sydney, Australia on Saturday night.
The 32-year-old American, who was only brought into the title picture following an injury to Dricus du Plessis, won a unanimous decision to pull off one of the biggest upsets in UFC history.
Strickland enjoyed the better of the striking exchanges against his much-fancied opponent and was relentless on the front foot over the course of the five rounds.
The American, who was only fifth in the middleweight rankings going into the fight, dropped Adesanya with a right hand in the first round - a moment which seemed to give him the impetus to push on and establish himself as the aggressor for the rest of the bout.
Adesanya, appearing in his 11th title fight overall and first defence of his second reign as middleweight champion, failed to inflict any serious damage on Strickland, who the judges unanimously scored as the winner to hand him his first title in his first championship bout.
"Am I dreaming, am I going to wake up? Somebody hit me. Never in a million years did I think I would be here. I don't cry much but I'm trying to keep [myself] together right now," Strickland said after the fight.
"Izzy's had how many highlight knockouts, he's beaten the majority of my friends pretty easily. I was even doubting myself at times, but the fans in Australia motivated me.
"I give so many brain cells to the MMA gods every day. I thought I'd be walking away a little bloody and broken up, I'm still shocked that didn't happen, this is the first time I'm lost for words.
"But remember, this gold around my waist doesn't mean [anything]. What matters is how you live your life, and I'm living better through you guys, for you guys, thank you."
Strickland now has 28 wins from his 33 fights, while Adesanya was handed just the third defeat of his 27-fight career.
In the co-main event, Alexander Volkov choked out home favourite Tai Tuivasa in the second round, while elsewhere there were wins for Kevin Jousset, Gabriel Miranda, Chepe Mariscal, Carlos Ulberg, Tyson Pedro and Justin Tafa.