Adrian Curiel pulled off a huge upset against Sivenathi Nontshinga on Saturday night with a stunning knockout win.
Nontshinga had been expected to defend his IBF light-flyweight title in a routine defence in Monte Carlo, but Curiel had other plans.
In the second round of the fight, the Mexican launched an overhand right that caught South African opponent Nontshinga right on the chin.
The champion immediately collapsed and fell through the ropes, lying on his back on the canvas unconscious.
This comes despite the fact that Nontshinga was a 1/8 favourite going into the contest.
And Curiel had four previous defeats on his record, while Nontshinga was unbeaten.
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But, that is no longer the case as Nontshingahad to relinquish his world title at the hands of fellow 24-year-old Curie.
"It's an absolute dream for me this victory," Curiel said via translation after the fight.
"It's super important for me and my family, it's a victory for Mexico... I spoke to my mother and I said to her, no one's going to beat me tonight.
"When I started at six years old, this was my dream, and I think someone is looking down on me from up there right now."
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Nontshinga now joins other great boxing upsets in Anthony Joshua losing his titles to Andy Ruiz in 2019 and Mike Tyson's shock defeat to 42/1 underdog Buster Douglas in 1990.
Both heavyweights were previously unbeaten as was Joe Cordina who was putting his IBF super featherweight title on the line against America's Edward Vazquez in the main event in Monaco.
It was a hard-fought battle, but Cordina came out on top, winning by majority decision to move his record on to 17-0.
"It wasn't my best performance, but it still got the job done," he said afterwards.
"He didn't hurt me at any point. Nothing was happening so I felt like I had to ignite something. It probably wasn't my best idea. Don't make excuses, you lost the fight, end of story. I beat two champions back-to-back, come on man, you need to give me my flowers."
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