Undefeated Russian Dmitry Bivol scored by far the biggest win of his career on Saturday night when he outpointed the world's pound-for-pound top fighter, Saul 'Canelo' Alvarez, in a seismic upset in Las Vegas.
Multiple-division world champion Canelo had moved up in weight to challenge the 31-year-old WBA (Super) light-heavyweight champion but suffered defeat on the scorecards, with Bivol becoming just the second man to hand victory to Canelo in 61 fights.
It was the first time that Canelo has tasted defeat since he was beaten by majority decision by Floyd Mayweather in 2013 - with all three judges scoring the bout unanimously in Bivol's favor 115-113.
“I'm glad I proved myself, I'm the best in my division and I keep this belt,” said Bivol of the world title he has held since 2016.
“If you don't believe in yourself what do you do? You achieve nothing. I believe and my team believed in me.
“I felt his power. You can see on my arm, he beat my arm up but not my head. That's better.”
Canelo, who was heavily favored heading into the fight, took the loss in his stride but said that he will pursue revenge against the Russian champion.
“You have to accept it, it's boxing," he said afterwards. "He's a great champion. Sometimes in boxing you win and lose and I'm not giving excuses. I lost and he won.
“Yeah, of course [I want a rematch]. This doesn't end like this.”
Bivol, who immediately steps into the role of being one of Russia's all-time great fighters, said that he is more than willing to renew his rivalries with the Mexican champion.
“Let's talk about a rematch. I wanted this fight because I wanted to get the opportunity and I appreciate this opportunity.
“I'm ready for a rematch, I just want to be treated as the champion now.”
Bivol's win comes amid scrutiny from figures within the sport, notably the Ukrainian former heavyweight champion Wladimir Klitschko, who said that Bivol shouldn't have been permitted to compete given the actions of his country in Ukraine.
“It is important that this boxer [Bivol] is forbidden from fighting in America, just as all Russian athletes are being banned from international competition,” Klitschko told the BBC in recent days.
Three of the world's major sanctioning bodies for boxing - the WBC, WBO and IBF - have blocked fighters from Russia and Belarus from competing in world title bouts.
The WBA, for whom Bivol is a champion, have not taken similar measures.