A well-known tagline used for the UFC is “anything can happen”, and these incredible upsets prove just that.
While the best man or woman usually takes home the gold in the UFC, there are always upset victories and shock KOs that nobody saw coming.
Here are the biggest upsets in UFC history, ranked, starting with a Cinderella story and ending with the ultimate underdog victory by a The Ultimate Fighter winner.
5. Michael Bisping finally won UFC gold by a two-weeks notice win over Luke Rockhold
In what has been called a “Cinderella story” in the history of MMA, Michael Bisping had to wait 12 years before he finally became a champion in the UFC.
After a decade of trying and failing to secure a title shot, “The Count” got his opportunity to challenge Luke Rockhold at UFC 199 by chance.
When former champion Chris Weidman was forced to pull out of his clash with Rockhold just two weeks before the fight, Bisping was ready to step in at a moment’s notice to fulfill his destiny.
Despite being the total underdog in the fight, Bisping surprised everyone by knocking out the champion in the first round.
He knocked down Rockhold with a series of punches before the referee called the fight, awarding the Englishman a shock title win that nobody saw coming.
4. Sean Strickland dominated heavy favorite Israel Adesanya at UFC 293
It wasn’t the result of Sean Strickland’s win over Israel Adesanya that was the most surprising. It was the dominant fashion in which he destroyed the champion that made waves in the UFC.
Adesanya was the heavy favorite for their fight at UFC 293 and was the reigning UFC Middleweight champion.
He had only just regained the title from Alex Perreira and was intent on going on a dominant second reign as champion.
However, Strickland dominated Adesanya over 5 rounds, winning the UFC Middleweight championship handily in an impressive fashion that nobody saw coming.
Adesanya called the loss a “bad dream”, showing what he thought about the devastating loss at the hands of Strickland in Australia.
3. Ronda Rousey’s dominant run ended in KO by Holly Holm
There have been few fighters as dominant in their divisions as Ronda Rousey was in the early days of the UFC Women’s divisions.
However, that made Rousey’s knockout loss to Holly Holm at UFC 193 all the more shocking.
Rousey’s last UFC Women’s Bantamweight title defense was her eighth time defending the belt that she won in the first-ever women’s fight in the UFC.
However, she came into the bout with Holm, a former boxer, woefully unprepared. Her sparring footage was underwhelming, and she seemed intent on going toe-to-toe with the far more experienced boxer.
Even so, nobody could look past the dominant Rousey and she seemed certain to pick up another early KO victory.
That’s what made her a second-round knockout defeat even more outrageous. A big punch from Holm sent Rousey spinning, only to eat a massive kick to the head to knock her out and claim the UFC Women’s Bantamweight title.
2. Juliana Pena beat GOAT Amanda Nunes in a massive shock
Nobody in the world of MMA saw Amanda Nunes, commonly referred to as the greatest female fighter in UFC history, losing her UFC Women’s Bantamweight title to Julianna Pena.
However, that is exactly what happened in one of the biggest upsets in UFC history. Pena had a long road to becoming champion, which began with her debut in 2013 after winning The Ultimate Fighter.
Pena was a massive underdog against Nunes. The reigning champion hadn’t lost since 2014 and defended her title against some of the all-time greats, like Ronda Rousey, Valentina Shevchenko, and Cris Cyborg.
Nunes dominated the first round, and the fight seemed to be going as expected. However, that all changed in the second round, where Pena hit the champion with a series of perfect counter punches before taking her down to the mat.
With over a minute left in the round, Pena mounted the back of Nunes, forcing her to tap out to a rear-naked choke and forfeit her UFC Women’s Bantamweight championship in one of the biggest upsets in UFC history.
1. Matt Serra shocks the world by knocking out Georges St-Pierre
It’s unlikely anything will ever come close to being as big an upset as when Matt Serra shocked Georges St-Pierre at UFC 69.
Serra had come up through The Ultimate Fighter TV show, winning the fourth series to earn a shot at the UFC Welterweight championship.
That fight was against one of the all-time greats in the UFC. St-Pierre was a two-division champion in the UFC and is one of the greatest fighters to ever come out of Canada.
The Quebec native was heavily favored to beat Serra, whose inclusion in the main event was seen more as a selling point for The Ultimate Fighter than an actual earned title.
He quickly dispelled any notion that he wouldn’t be in the fight by flying out of the blocks, as Serra took the fight to the champion in the octagon.
He dropped St-Pierre multiple times in the first round, eventually mounting him and ground-and-pounding him into the mat as the crowd and Joe Rogan on commentary exploded with excitement.
Serra came out of nowhere to become the new world champion, shocking the world with the greatest upset in MMA history.
St-Pierre may have avenged his loss later on, but he can never take that win away from Serra.