Boxing has always thrived on unpredictability. No matter how dominant a champion appears, it only takes one punch, one moment, or one mistake to rewrite history. The biggest boxing upsets in history are the moments that shocked the world, humbled legends, and proved why the sport remains one of the most dramatic in all of athletics.
This list ranks the biggest boxing upsets in history from 10 to 1, based on the scale of the shock, the stakes involved, and the lasting impact on the sport.
10. Hasim Rahman vs Lennox Lewis (2001)
Few expected Hasim Rahman to trouble Lennox Lewis, who entered the fight as the undisputed heavyweight champion. Lewis was widely seen as untouchable at the time.
That perception changed instantly when Rahman landed a devastating right hand in the fifth round, knocking Lewis out cold. The result stunned fans and forced an immediate rematch, which Lewis later won, but the shock of that night remains unforgettable.
9. Oliver McCall vs Lennox Lewis (1994)
Before Rahman, Lennox Lewis had already been on the wrong end of another major upset. Oliver McCall, considered a heavy underdog, knocked out Lewis in the second round to claim the heavyweight title.
The abrupt nature of the defeat and the dominance Lewis had shown prior made this one of the earliest major shocks of the modern era.
8. Andy Ruiz Jr. vs Anthony Joshua (2019)
Anthony Joshua was expected to make a successful U.S. debut against late replacement Andy Ruiz Jr. Instead, Ruiz delivered one of the most shocking performances in heavyweight history.
After being dropped early, Ruiz responded with relentless pressure and fast combinations, stopping Joshua in the seventh round. The upset reshaped the heavyweight division overnight.
7. James Douglas vs Mike Tyson (1990)
Known as Buster Douglas, James Douglas entered his fight against Mike Tyson as a 42-1 underdog. Tyson was undefeated and widely regarded as the most feared fighter in the world.
Douglas delivered a disciplined and fearless performance, knocking Tyson out in the 10th round. It remains one of the most iconic moments in boxing history.
6. Leon Spinks vs Muhammad Ali (1978)
Leon Spinks had only seven professional fights when he challenged Muhammad Ali for the heavyweight title. Few believed he stood a chance against a global icon.
Spinks outworked Ali over 15 rounds to win a split decision, creating one of the most surprising title changes the sport has ever seen.
5. Michael Moorer vs George Foreman (1994)
(Photo by The Ring Magazine via Getty Images)
At 45 years old, George Foreman was seen as a relic of a past era when he faced the younger and faster Michael Moorer.
Foreman trailed on the scorecards before landing a perfectly timed right hand in the 10th round to reclaim the heavyweight title. The victory made him the oldest heavyweight champion in history and completed one of boxing’s greatest comebacks.
4. Evander Holyfield vs Mike Tyson (1996)
Mike Tyson returned to dominance in the mid-1990s and was heavily favored against Evander Holyfield, who many believed was past his best.
Holyfield shocked the world with a tactical and physical masterclass, stopping Tyson in the 11th round. The result redefined both fighters’ legacies and set up their infamous rematch.
3. Sugar Ray Leonard vs Marvin Hagler (1987)
Sugar Ray Leonard came out of retirement to face the dominant Marvin Hagler, who had ruled the middleweight division for years.
Despite the odds, Leonard used speed, movement, and ring intelligence to secure a controversial split decision victory. The result remains one of the most debated upsets in boxing history.
2. Joe Frazier vs Muhammad Ali (1971)
Known as the “Fight of the Century,” this bout saw Joe Frazier face Muhammad Ali, who was returning after a long absence.
Ali was expected to reclaim his dominance, but Frazier produced a relentless performance, culminating in a famous knockdown in the 15th round. The unanimous decision victory marked a defining moment in heavyweight history.
1. James Douglas vs Mike Tyson (1990)
No upset in boxing history compares to Buster Douglas defeating Mike Tyson. Tyson was undefeated, undisputed, and seemingly invincible.
Douglas, given almost no chance, delivered the performance of his life, combining discipline, power, and composure. His knockout victory in Tokyo remains the gold standard for underdog triumphs in boxing.
Why These Upsets Still Matter
The biggest boxing upsets in history are more than just surprising results. They capture the essence of the sport, where preparation, belief, and opportunity can overcome even the widest odds.
These moments remind fans that no fighter is unbeatable. They also elevate boxing’s global appeal, as unpredictability keeps audiences engaged and emotionally invested.
Conclusion
From shocking knockouts to unlikely decisions, the biggest boxing upsets in history have shaped the sport in unforgettable ways. Each fight on this list tells a story of resilience, belief, and the unpredictable nature of boxing.
As new fighters rise and new champions emerge, the possibility of another historic upset is always present. That uncertainty is what makes boxing timeless, and why fans continue to watch, knowing that history can be made at any moment.
