The 20 Greatest Upsets in Boxing and Combat Sports History, Ranked

In combat sports, few moments capture the imagination quite like a stunning upset—when the underdog defies all odds to achieve the impossible. These moments transcend sport, becoming cultural touchstones that remind us why we watch. But what makes an upset truly great? Our ranking considers four key criteria: the magnitude of the odds differential, the significance of the fight, the method of victory, and the lasting cultural impact.

From ancient gladiatorial contests to modern MMA octagons, upsets have always been the heartbeat of combat sports. They humble champions, create legends overnight, and prove that in a sport where two warriors enter and only one leaves victorious, certainty is an illusion.

#20: Holly Holm Defeats Ronda Rousey (UFC 193, 2015)

Ronda Rousey entered UFC 193 as the most dominant force in women's MMA, undefeated in 12 fights with 11 finishes. Holly Holm, despite being a decorated boxer, was seen as just another victim for Rousey's armbar factory.

What made this upset extraordinary was how Holm dismantled Rousey's aura of invincibility. Using precise footwork and crisp striking, Holm avoided Rousey's takedown attempts and systematically broke down the champion. The knockout came via a perfectly timed head kick in the second round—delivered with surgical precision to a bloodied and bewildered Rousey.

The cultural impact was immediate. Rousey's defeat marked the end of her mainstream crossover appeal and highlighted the evolution of women's MMA from grappling dominance to well-rounded skill sets.

#19: Frankie Edgar Defeats BJ Penn (UFC 112, 2010)

BJ Penn was considered by many the greatest lightweight of all time when he faced Frankie Edgar at UFC 112. Penn, the defending champion, had looked unstoppable in recent title defenses, while Edgar was viewed as an undersized wrestler without knockout power.

Edgar's victory came through relentless pace, superior conditioning, and tactical brilliance. He outworked the legendary Penn over five rounds, using constant movement and volume striking to earn a unanimous decision. The upset was so shocking that many observers, including Penn himself, called for an immediate rematch—which Edgar won even more decisively.

#18: Matt Serra Defeats Georges St-Pierre (UFC 69, 2007)

Georges St-Pierre entered UFC 69 as the welterweight champion and one of MMA's rising superstars. Matt Serra, a veteran journeyman who had won The Ultimate Fighter 4 tournament, was given little chance against the athletic and skilled Canadian.

The upset came early and violently. Serra caught St-Pierre with a right hook that wobbled the champion, then followed up with a barrage of punches that forced referee John McCarthy to stop the fight at 3:25 of the first round. The victory was so unexpected that it temporarily derailed what many considered St-Pierre's inevitable path to greatness.

#17: Leon Edwards Defeats Kamaru Usman (UFC 278, 2022)

Kamaru Usman had dominated the welterweight division for over three years, successfully defending his title five times and riding a 19-fight winning streak. Leon Edwards, despite being highly skilled, was seen as lacking the finishing ability to threaten Usman.

With less than a minute remaining in the fifth round and trailing on all scorecards, Edwards landed a picture-perfect head kick that dropped Usman and changed the trajectory of the welterweight division. The timing and dramatic nature of the knockout—coming when Edwards needed a finish to win—elevated this upset beyond its odds differential.

#16: Gabriel Gonzaga Defeats Mirko "Cro Cop" Filipovic (UFC 70, 2007)

Mirko Filipovic entered the UFC as one of the most feared strikers in heavyweight MMA, fresh from his legendary PRIDE career where his left high kick had become synonymous with devastating knockouts. Gabriel Gonzaga was a relatively unknown Brazilian with solid grappling but unremarkable striking.

The irony was palpable when Gonzaga knocked out Filipovic with the Croatian's own signature weapon—a left high kick—in the first round. The knockout was so clean and unexpected that it immediately became one of the most replayed finishes in UFC history, proving that in MMA, anyone can be beaten with their own techniques.

#15: Kazushi Sakuraba Defeats Royce Gracie (PRIDE Grand Prix 2000 Finals)

Royce Gracie was the original UFC champion and the man who introduced Brazilian Jiu-Jitsu to the world. When he faced Kazushi Sakuraba in a no-time-limit, no-judges fight, Gracie was expected to showcase the superiority of his family's martial art. Sakuraba, while skilled, was seen as undersized and outmatched against the Gracie mystique.

Sakuraba's victory came through superior conditioning and evolved grappling. He controlled Gracie on the ground for over 90 minutes, eventually forcing Gracie's corner to throw in the towel due to exhaustion and damage. This upset effectively ended the Gracie family's aura of invincibility in MMA and established Sakuraba as "The Gracie Hunter."

#14: Andy Ruiz Jr. Defeats Anthony Joshua (June 1, 2019)

Anthony Joshua was the unified heavyweight champion, undefeated in 22 fights with 21 knockouts, making his American debut at Madison Square Garden. Andy Ruiz Jr. was a late replacement opponent who had been knocked down by Joseph Parker and was coming off a decision loss. Joshua was an overwhelming favorite.

Ruiz shocked the boxing world by dropping Joshua four times en route to a seventh-round TKO victory. The Mexican-American's hand speed and boxing IQ proved superior to Joshua's physical advantages, sending shockwaves through the heavyweight division while launching Ruiz to international stardom.

#13: Forrest Griffin Defeats Tito Ortiz (UFC 59, 2006)

Tito Ortiz was one of the UFC's biggest stars and a former light heavyweight champion seeking to reclaim his title. Forrest Griffin was a fan favorite from The Ultimate Fighter but was considered outmatched against Ortiz's wrestling and experience.

Griffin's unanimous decision victory was built on heart, conditioning, and tactical improvements that caught Ortiz off-guard. The win launched Griffin toward an eventual title shot and helped establish The Ultimate Fighter alumni as legitimate contenders, not just reality TV personalities.

#12: Michael Bisping Defeats Luke Rockhold (UFC 199, 2016)

Luke Rockhold was the defending middleweight champion who had dominated Michael Bisping in their first encounter. Bisping took the rematch on short notice, and Rockhold was so confident that he admitted to not training seriously for the fight.

Bisping's first-round knockout via left hook was the culmination of years of persistence and improvement. The victory made Bisping the first British UFC champion and proved that dedication and opportunity could overcome superior athleticism and past defeats.

#11: Robbie Lawler Defeats Rory MacDonald (UFC 189, 2015)

While not a massive betting upset, this fight deserves inclusion for the dramatic nature of the comeback. Rory MacDonald was dominating Robbie Lawler through four rounds, appearing destined to win the welterweight title. MacDonald was ahead on all scorecards entering the fifth round.

Lawler's fifth-round TKO victory, achieved after breaking MacDonald's nose with a devastating jab, represents one of the greatest championship comebacks in UFC history. The image of MacDonald's bloodied face became iconic, while Lawler's warrior spirit in adversity defined his championship reign.

#10: Nate Diaz Defeats Conor McGregor (UFC 196, 2016)

Conor McGregor was the UFC's biggest star, coming off a 13-second knockout of José Aldo and moving up two weight classes to face Nate Diaz on short notice. McGregor's striking prowess and confidence made him a modest favorite despite the short notice and weight jump.

Diaz's second-round rear naked choke submission victory shocked the MMA world and temporarily halted McGregor's meteoric rise. The upset demonstrated that McGregor's power didn't translate to higher weight classes and that his ground game remained vulnerable. The cultural impact was massive, spawning countless memes and establishing Diaz as a superstar.

#9: Antonio Tarver Defeats Roy Jones Jr. (May 15, 2004)

Roy Jones Jr. was considered by many the pound-for-pound best fighter in the world, having recently captured the heavyweight title from John Ruiz. Antonio Tarver had lost a controversial decision to Jones just five months earlier.

Tarver's second-round knockout with a perfect left hook ended Jones's aura of invincibility and marked the beginning of his decline. The upset was particularly shocking because Jones had seemed untouchable at light heavyweight, and Tarver's power had never been considered elite-level.

#8: Chris Weidman Defeats Anderson Silva (UFC 162, 2013)

Anderson Silva had not lost a fight in over seven years and was widely considered the greatest mixed martial artist of all time. Chris Weidman was an undefeated but relatively untested challenger who many saw as another victim for Silva's highlight reel.

Weidman's second-round knockout came when Silva, showboating with his hands down, was caught by a perfectly timed left hook. The upset ended the longest title reign in UFC history at 2,457 days and 16 consecutive wins. The cultural impact was seismic—Silva's invincibility was shattered in the most unexpected way possible.

#7: Fedor Emelianenko Defeats Mirko "Cro Cop" Filipovic (PRIDE Final Conflict 2005)

While Fedor was already established as an elite heavyweight, Mirko Filipovic was riding a nine-fight winning streak in PRIDE and was considered by many to have the tools to defeat the Russian. Filipovic's knockout power made him a slight favorite among some analysts.

Fedor's unanimous decision victory, achieved through superior grappling and ground control, established him as the undisputed #1 heavyweight in the world. The upset was significant because it demonstrated Fedor's ability to neutralize the most dangerous striker in the division using pure technique and fight IQ.

#6: Joaquin Buckley's Flying Knee Against Impa Kasanganay (UFC Fight Island 5, 2020)

While this wasn't a massive betting upset, Buckley's spinning heel kick knockout deserves inclusion for being one of the most spectacular finishes in recent UFC history. The technique—catching Kasanganay's kick, spinning, and landing a heel kick while airborne—was so extraordinary that it transcended the sport and became a viral sensation worldwide.

#5: Miesha Tate Defeats Holly Holm (UFC 196, 2016)

Holly Holm entered as the bantamweight champion fresh off her stunning knockout of Ronda Rousey. Miesha Tate was seen as a stylistic mismatch—a grappler who had already lost twice to Rousey and whose striking was considered inferior to Holm's boxing pedigree.

Tate's fifth-round rear naked choke victory was stunning in its timing and execution. Trailing on the scorecards, Tate secured a takedown with less than two minutes remaining and quickly transitioned to the submission. The upset prevented Holm from establishing herself as a dominant champion and set up Tate's eventual showdown with Amanda Nunes.

#4: Buster Douglas Defeats Mike Tyson (February 11, 1990)

Mike Tyson was the undisputed heavyweight champion, undefeated in 37 fights with 33 knockouts, and was considered invincible. James "Buster" Douglas was a massive underdog, with some reports suggesting odds as high as 42-1 against him.

Douglas's tenth-round knockout of Tyson in Tokyo sent shockwaves around the world. The upset was achieved through superior boxing technique, reach advantage, and perhaps most importantly, Douglas fighting with the motivation of his recently deceased mother's memory. The cultural impact was enormous—Tyson's aura of invincibility was shattered, and the heavyweight division was thrown into chaos.

#3: Matt Serra's Victory Over GSP—The Full Impact

Returning to Matt Serra's victory over Georges St-Pierre with deeper context, this upset deserves higher ranking due to its immediate and lasting impact on the welterweight division. Serra, a 30-year-old veteran who had never been considered elite-level, suddenly found himself as UFC welterweight champion.

The upset was particularly shocking because St-Pierre was not just champion but was being groomed as the face of the UFC's expansion into Canada and Europe. Serra's victory temporarily derailed those plans and proved that in MMA, any fighter with knockout power could change the landscape in seconds.

#2: Dan Henderson Defeats Fedor Emelianenko (Strikeforce, July 30, 2011)

Fedor Emelianenko had been undefeated for nearly ten years and was widely considered the greatest heavyweight of all time. Dan Henderson, at 41 years old, was seen as past his prime despite his legendary status.

Henderson's first-round TKO victory, achieved with his signature right hand, ended Fedor's mystique and marked the definitive end of his PRIDE-era dominance. The upset was particularly significant because it came from an aging legend defeating the man many considered the GOAT, proving that power is often the last thing to go in combat sports.

#1: Kazushi Sakuraba Defeats Royler Gracie (PRIDE 8, 1999)

Taking the top spot is Kazushi Sakuraba's submission victory over Royler Gracie, which deserves recognition as one of the greatest upsets in combat sports history. Royler Gracie was not just a champion but represented the Gracie family's legacy in vale tudo competition. Sakuraba was a professional wrestler with limited MMA experience.

The upset was achieved through pure technique—Sakuraba submitted Royler with a kimura, using the Gracies' own art against them. This victory launched Sakuraba's legendary career as "The Gracie Hunter" and proved that Japanese fighting spirit and technique could overcome Brazilian Jiu-Jitsu dominance. The cultural impact extended beyond sport, representing a clash of martial arts philosophies and national pride.

The upset was so significant that it changed the trajectory of MMA, proving that no single martial art or family could claim superiority in mixed martial arts competition.

Honorable Mentions

Several upsets narrowly missed our top 20: TJ Dillashaw's knockout of Cody Garbrandt, which ended their bitter rivalry; Yair Rodriguez's last-second elbow knockout of Chan Sung Jung; and additional comeback victories that showcased championship heart in its purest form.