In the UFC, injuries are the main reason fighters pull out of a scheduled bout. UFC matchmakers, in turn, are forced to look for a replacement fighter who's willing to step up on short notice.
More often than not, replacement fighters lose due to the lack of a complete training camp. But every once in a while, the replacement fighter overcomes the odds and pulls off an upset. These rare occasions are some of the most remarkable moments in UFC history.
Few names stand out when it comes to epic replacement fighter wins in the UFC. Find out who they are:
#5 Georges St-Pierre at UFC 79
UFC great Georges St-Pierre admitted that losing to Matt Serra took a toll on his mental health. GSP revealed that the only thing on his mind since dropping the UFC welterweight title at UFC 69 was revenge against Serra.
However, St-Pierre had to work hard to earn his shot at redemption. Instead of being rewarded with an immediate championship rematch, GSP faced Josh Koscheck and emerged victorious in a title eliminator.
On the other hand, Serra was scheduled to defend his welterweight title against Matt Hughes after the pair served as rival coaches in The Ultimate Fighter 6. However, Matt Serra was forced to withdraw due to a back injury.
St-Pierre capitalized on the opportunity. The French-Canadian legend stepped up as a replacement fighter to face Hughes in a trilogy fight at UFC 79.
Despite having just five weeks to train for an interim title fight with Hughes, St-Pierre did not perform like a typical replacement fighter. GSP forced Hughes to tap out in round two to book a rematch with Serra.
Four months later, St-Pierre would kickstart a five-year reign as welterweight champ after reclaiming the title from Matt Serra at UFC 83.
#4 Daniel Cormier at UFC 187
After losing to Jon Jones in the main event of UFC 182, Daniel Cormier was given a second chance to capture the UFC light heavyweight title as a replacement fighter.
Jones was scheduled to take on what fans and critics believed would be his toughest test yet in Anthony 'Rumble' Johnson. However, Jones was involved in a hit-and-run accident over a month before the UFC 187 pay-per-view. The UFC, in turn, decided to strip Jones of the title and announced Cormier as a replacement fighter.
'DC' overcame a slow start to defeat 'Rumble' and seize the light heavyweight throne. The most memorable part of the night came when Cormier sent a message to his bitter rival during the post-fight interview.
#3 Michael Bisping at UFC 199
British superstar Michael Bisping was given an opportunity to fulfill his life-long goal and avenge a loss at the same time. He made the most of this opportunity in one of the most unforgettable moments inside the octagon.
Luke Rockhold choked out Bisping at UFC Fight Night 55. The Englishman bounced back by winning three in a row against CB Dollaway, Thales Leites, and UFC legend Anderson Silva.
Several months later, Bisping was given an opening when Chris Weidman pulled out of his rematch with Rockhold due to a neck injury. With only 17 days to prepare, Bisping stepped up as a replacement fighter to challenge for the title.
The quintessential TUF (The Ultimate Fighter) winner defied overwhelming odds by knocking out Rockhold in round one to capture the title that had eluded him for several years.
#2 Nate Diaz at UFC 196
Conor McGregor was the UFC's hottest star in 2016. The Irishman was planning to raise his stock even further by collecting a second title against then-UFC lightweight champion Rafael dos Anjos.
But fate had other plans.
The super-fight between McGregor and dos Anjos was canceled after the Brazilian broke his foot several days before the pay-per-view event. But the UFC stumbled upon a more intriguing matchup when Nate Diaz agreed to fight McGregor as a replacement fighter.
It was reported that Diaz was partying on a yacht in Cabo when the UFC offered him the fight. With only 13 days left to prepare, Diaz took the offer with no hesitation.
Come UFC 196, Diaz turned in one of the most spectacular performances in the octagon by a replacement fighter. He choked out then-featherweight titleholder Conor McGregor, handing 'Notorious' his first defeat in the UFC.
#1 Jon Jones at UFC 128
One man's tragedy is another man's blessing. That was the story of UFC 128 when Jon Jones, who was a replacement fighter, defeated Mauricio 'Shogun' Rua to become the youngest champion in UFC history.
Rashad Evans earned an opportunity to reclaim the UFC light heavyweight title against 'Shogun' at UFC 128. Unfortunately, 'Suga' was forced to pull himself out of the title match after injuring his knee in training camp.
The UFC decided to offer the title opportunity to Evans' then-teammate Jon Jones, who was only too happy to oblige. Jones, who agreed to fight on short notice, eviscerated 'Shogun' to capture the light heavyweight title. The rest, of course, is history.
Rashad Evans left the renowned Jackson-Wink MMA gym in Albuquerque, New Mexico, for a chance to challenge 'Bones' for the title. Unfortunately, the title would forever elude Evans after Jon Jones became the champion.