The 10 Biggest Upsets in UFC History

Nobody remembers the fights that go to form. What sticks in the memory is the night the unbeatable champion gets flattened. That is the beauty of the UFC. Styles make fights. One punch changes everything. As a result, the biggest favourite in the building can end up face down before the first round is out.

The fights below broke the bank and broke the script. Each one turned a heavy underdog into a champion or a legend. Moreover, each one sent a shockwave through the sport that still echoes today. We ranked them using the betting odds, the stakes, and the sheer disbelief of the moment.

So this is our countdown of the ten biggest upsets in UFC history. For the odds on the next card and the next potential shock, head over to our UFC betting markets.

1. Matt Serra TKO 1 Georges St-Pierre (UFC 69, 2007)

The gold standard. When people argue about the biggest upset in UFC history, this fight ends the argument. Georges St-Pierre was the most complete welterweight on the planet. In fact, he sat as a -1300 favourite. He defended his title against a short-notice challenger who had won a reality TV show. Matt Serra came in as a +800 underdog. He stood five foot six and carried a journeyman’s record. Almost nobody outside his own gym gave him a chance.

Then everything changed. Serra landed a looping overhand right behind GSP’s ear midway through the first round. The champion’s legs buckled. Serra swarmed him, dropped him repeatedly, and forced the stoppage at 3:25 of round one. Suddenly the man many call the greatest welterweight ever had lost to a supposed stepping stone. One famous punter even turned $37,000 into $259,000 backing Serra at 7-to-1. Nearly two decades on, it remains the benchmark for every other UFC shock.

2. Holly Holm KO 2 Ronda Rousey (UFC 193, 2015)

This one was the most seismic of all. Ronda Rousey was not just a champion. Instead, she was a global phenomenon who had transcended the sport. She had finished her previous three opponents in a combined 64 seconds. Moreover, she had appeared in Hollywood films and looked genuinely unbeatable. The odds told the story. Rousey sat around -1400, while Holm came in at +700 or bigger.

Holm had boxed at world level for years. Therefore, she knew exactly how to fight on the feet. She refused to engage Rousey’s grappling. Instead, she stuffed the takedowns and picked her apart in front of 56,000 fans in Melbourne. Then, late in the second round, she landed a perfect left head kick. Rousey went out cold. It is still one of the most famous knockouts in UFC history. In a single night, it ended the aura of the sport’s biggest ever star.

3. Julianna Peña Sub 2 Amanda Nunes (UFC 269, 2021)

Amanda Nunes was, by consensus, the greatest female fighter to ever live. She had knocked out Ronda Rousey in 48 seconds. Likewise, she had flattened Cris Cyborg in 51. She held two divisional titles at once. On top of that, she rode a 12-fight win streak into her bantamweight defence. Julianna Peña, meanwhile, came in as a +700 underdog. Most saw her as an overmatched challenger.

Peña had other ideas. First, she weathered Nunes’s early power. Then she kept marching forward and broke the champion in the second round. She hurt Nunes with punches, took her back, and locked up a rear-naked choke for the tap. Just like that, the most dominant woman in the sport’s history had lost. As a result, it ranks among the greatest upsets the promotion has ever seen.

4. Michael Bisping KO 1 Luke Rockhold (UFC 199, 2016)

This is the one every British fan remembers. Michael Bisping had grafted in the UFC for a decade without a world title. He had lost two title eliminators along the way. As a result, many wrote him off as the nearly man of the middleweight division. Then champion Luke Rockhold needed a late replacement at UFC 199. Bisping took the fight on 17 days’ notice as a +525 underdog. Rockhold had even submitted him once before, back in 2014.

What followed became British MMA folklore. Early in the first round, Bisping caught an overconfident Rockhold with a left hook. The champion crashed to the canvas. Bisping pounced with follow-up shots and finished it at 3:36 of round one. Incredibly, The Count was now UFC Middleweight Champion of the World. He was 37 years old and had taken the fight on a fortnight’s notice. No British fighter had won a UFC title in the modern era before that night. Still, it remains one of the most beloved moments in the country’s combat sports history.

5. Fabricio Werdum Sub 1 Fedor Emelianenko (Strikeforce, 2010)

Technically this was a Strikeforce fight, not a UFC one. Still, no list of MMA’s greatest upsets can leave it out. Both men later fought in the UFC anyway. Fedor Emelianenko had gone unbeaten for nearly a decade. Many regarded him as the greatest heavyweight ever. He opened as roughly a -1100 favourite. Most saw Werdum, a jiu-jitsu specialist, as a clear tier below the Russian.

Early on, Fedor did exactly what everyone expected. He dropped Werdum with a punch inside the first minute. Then he made the one mistake Werdum wanted and dived into his guard. The Brazilian locked up a triangle, switched to an armbar, and Fedor tapped at 1:09. In one sequence, the myth of Fedor’s invincibility collapsed. Werdum later became UFC heavyweight champion. Even so, this stays the defining moment of his career.

6. Sean Strickland Decision Israel Adesanya (UFC 293, 2023)

This was one of the most one-sided upsets on the entire list. Israel Adesanya was a two-time middleweight champion. He also sat inside the ESPN top-five pound-for-pound rankings. Sean Strickland, by contrast, came in as a +500 underdog. Fans knew him more for his outrageous press conferences than his fighting. Most saw the bout as a tune-up before Adesanya’s grudge match with Dricus du Plessis.

Instead, Strickland ripped up the script. First, he dropped Adesanya with a right hand in the opening round. Then he leaned on his Philly Shell defence and a relentless jab. For five full rounds, he walked the champion down. In the end, he out-landed Adesanya 101 strikes to 73 and swept every scorecard 49-46. It was the largest betting upset in UFC middleweight title history. Crucially, Strickland won with a dominant performance, not a lucky punch.

7. TJ Dillashaw TKO 5 Renan Barão (UFC 173, 2014)

At the time, many ranked Renan Barão as a top-three pound-for-pound fighter. He had not lost in nearly a decade, a run of over 30 fights. Naturally, he opened as a -1000 favourite. TJ Dillashaw came in at +650, and few expected him to last.

Instead, Dillashaw delivered a coming-of-age performance. He used constant movement, angles and feints. As a result, the champion spent the night chasing shadows. First, he dropped Barão in the opening round. Then he controlled the fight throughout and finished him with strikes in the fifth. That win announced Dillashaw as an elite bantamweight. It also ended one of the sport’s most dominant unbeaten runs.

8. Chris Weidman KO 2 Anderson Silva (UFC 162, 2013)

Anderson Silva rode a 16-fight UFC win streak into this one. He had never lost inside the Octagon. Almost everyone regarded him as the greatest mixed martial artist alive. Chris Weidman, meanwhile, was unbeaten but unproven, with just nine fights. He was not a huge underdog. Even so, almost nobody believed he could dethrone the legend.

In the end, Silva’s own showmanship undid him. He clowned and dropped his hands to taunt Weidman. This time, though, he left himself exposed. Weidman made him pay with a clean left hook and knocked him out cold in the second round. Just like that, the most dominant champion in UFC history had fallen. Because he lost to his own arrogance, the shock landed even harder.

9. Frankie Edgar Decision BJ Penn (UFC 112, 2010)

BJ Penn was a lightweight force of nature. Few fighters in the division had ever matched his natural gifts. At the time, he was dominating his title reign. Frankie Edgar, by contrast, was a smaller, lightly-regarded challenger and a heavy underdog. Most expected Penn to handle him comfortably.

Instead, Edgar simply refused to stop moving. He used relentless footwork, volume and in-and-out boxing. For five rounds, he peppered Penn and never let the champion set his feet. The unanimous decision stunned the arena. Then Edgar backed it up in the rematch, beating Penn even more clearly. As a result, he launched one of the most respected title runs in lightweight history.

10. Stipe Miocic KO 1 Fabricio Werdum (UFC 198, 2016)

Finally, a heavyweight shock in front of a hostile crowd. Fabricio Werdum was the reigning heavyweight champion after beating Cain Velasquez. He defended in his native Brazil against Stipe Miocic. Behind him stood 45,000 partisan fans. Naturally, Werdum was the favourite.

Miocic kept it simple and let his hands go. As Werdum lunged in recklessly behind a jab, Miocic met him with a short counter right hand. The champion dropped instantly, and the fight ended in the first round. In short, it was textbook heavyweight violence, where one clean shot flips a fight. Ultimately, it launched Miocic towards becoming the most successful heavyweight champion in UFC history.

What Makes a Great UFC Upset?

Look across this list and the same patterns repeat. First, a dominant champion walks into a fight everyone assumes is a formality. Then an overlooked challenger arrives with one specific edge. For Holm, it was footwork, for Serra, it was a right hand and for Peña, it was pressure. Finally, the favourite gets careless or gets caught. In many cases, it came down to a single submission or one clean punch. That is exactly why MMA is the most unpredictable sport on earth.

The other lesson is simple, and every seasoned fan already knows it. In a sport where fights end in an instant, the moneyline favourite is never a certainty. Moreover, a five-round championship fight offers countless ways to tear up the script. Of course, it helps to understand how fights are scored. Knowing how the UFC round structure works helps you spot where an underdog might find their opening.

Betting on UFC Upsets

For bettors, upsets are where the real value lives. Backing a heavy underdog can deliver enormous returns. Just ask anyone who put money on Serra, Holm or Strickland. Still, the key is understanding why an underdog might have a live chance. Look for a favourable style match-up, a durable chin, a real finishing threat, or a champion in decline.

Method of Victory markets add another layer. Often, they pay out at far longer odds than the moneyline. For example, backing an underdog to win by knockout or submission can turn a small stake into a serious return. In the end, the fights on this list prove one thing. In the UFC, no favourite is ever truly safe, and no underdog is ever truly out of it.