When Underdogs Defied the Odds: Biggest Upsets in Sports History

The biggest upsets in sports history made oddsmakers look foolish, underdogs famous, and bettors rich.

In this blog, we’re diving into the shocks that flipped the script, busted a few bets, and reminded everyone that favourites don’t always get the memo.

Key Takeaways:

• Even the biggest sporting giants have fallen to underdogs (e.g., Mike Tyson).
• Leicester City’s Premier League run remains the biggest betting upset in history. 
• No sport is safe from the next shock that flips predictions.

Let’s revisit the shocking moments that rewrote sporting history: Buster Douglas’ KO, Tom Brady’s ice-cold Super Bowl-winner, and others.

We’ll also tell you some Cinderella stories that still give fans goosebumps: from Leicester City's 5000.00-odds miracle to US hockey players stunning the Soviet team on the road to Olympic gold.

Strap in, we’re taking you on a journey to stories that shook the sports universe.

Football’s Biggest Upset: Leicester City Win the English Premier League

Leicester City’s 2015–16 Premier League triumph isn’t just football’s most inspiring Cinderella story; it’s arguably the biggest upset in sports history.

The Foxes entered the season as relegation candidates, priced at 5000.00 odds to win the title.

But one man, Leigh Herbert, a carpenter from England, turned out to be either the luckiest bettor alive (or should we say, a quiet genius?). He put £5 on Leicester City to win the league. 

From a betting perspective, this seemed too ambitious, given that the team had barely escaped relegation the year before.

More doubts were cast after the Foxes drew 1-1 in an exhibition game against a League Two team, Mansfield Town, in the pre-season. Yet, Leicester managed to shred every prediction model known to mankind. 

Under the calm guidance of Claudio Ranieri and powered by future club legends Jamie Vardy, Riyad Mahrez, and N’Golo Kanté, the Foxes made history.

They went on to win their first-ever Premier League title. Although surprises do happen in football, this was the only time that such a huge underdog triumphed.

*image courtesy of Shutterstock

Other Memorable Upsets in Football

World Cup Debutants Senegal Floor Champions France 

At the 2002 World Cup, Senegal pulled off a real “David beats Goliath” moment against France. 

This was the first time “The Lions of Teranga” qualified for this tournament. The French, meanwhile, were the defending champs, having won the trophy four years earlier.

Greek Gods Pull Off a Divine Feat at Euros 

When it comes to the Euros, the biggest Cinderella story happened in 2004 when Greece became continental champions. 

Before the tournament, their odds were 150.00, but they still managed to do the unimaginable. 

Thanks to their ultra-defensive approach, they kept a clean sheet in each knockout-phase game. In the final, they beat the tournament hosts, Portugal, 1–0.   

The Birth of “The Special One”: Porto’s Shocking UCL Triumph

Two years later, we saw a similar underdog story unfold in Europe, this time at the club level. Led by José Mourinho, FC Porto won the Champions League, despite starting their journey as 50.00-odds underdogs.

On their road to the title, Mourinho’s boys defeated a couple of heavyweights, including Monaco in the final.

Biggest Upset in Boxing: Buster Douglas Knocks Mike Tyson Out

Buster Douglas was the man responsible for the biggest defeat of Mike Tyson’s career. This happened in 1990, when Iron Mike was widely regarded as the best boxer on the planet.

For three years, he had been the undisputed heavyweight champion, so it’s no surprise that he felt confident ahead of the bout with Douglas.

The champ was heavily favoured, and the challenger was priced at 43.00 odds. With sports betting legal only in Nevada at the time, Las Vegas sportsbooks were practically daring people to put money on him. Almost nobody did.

But on that February night, Douglas produced the performance of a lifetime. 

Even though it initially looked as if Tyson was going to get the job done easily, Douglas refused to surrender. He even bounced back to his feet after an eighth-round knockdown.

Then came the moment that rewrote history: Douglas’ lightning-fast combination in Round 10 sent Tyson searching for his mouthpiece on the canvas.

The champion was finished, the world was stunned, and Douglas delivered a reminder that in boxing, no favourite is untouchable.

*image courtesy of Shutterstock

Other Huge Boxing Upsets

Rumble in the Jungle: Muhammad Ali Beats George Foreman

Muhammad Ali added another chapter to sports history with a huge upset over George Foreman in 1974. Known as “The Rumble in the Jungle,” the fight saw Ali’s swan song sung aloud.

Foreman entered the fight as a terrifying knockout machine: 40–0, with 37 KOs, fresh off destroying Joe Frazier and Ken Norton in just two rounds each.

Ali, meanwhile, was seen as past his prime. Oddsmakers had him as a heavy underdog (around 4.00–5.00), and many feared he’d be seriously hurt. 

Instead, Ali flipped the script with his now-legendary rope-a-dope. This tactic helped him drain Foreman’s battery, so it wasn’t too hard for Ali to land the fight-winning knockout in the eighth round.

Hasim Rahman’s KO Nobody Saw Coming

Another big boxing upset came in 2001, when the world witnessed Lennox Lewis being KO'd by Hasim Rahman. One sledgehammer right hand in Round 5 flipped the heavyweight division upside down.

Lewis learned his lesson, though, and got his revenge a few months later. Then, in the next fight, he beat Mike Tyson, and then did the same against Vitali Klitschko.

Andy Ruiz Ruins AJ’s Big Night

Fast-forward to 2019, and another huge betting surprise happened. Anthony Joshua was meant to walk through Andy Ruiz Jr. at New York’s Madison Square Garden. 

At the time, AJ was hyped as a potential GOAT of boxing, heading into his 23rd straight win. But Ruiz had different plans. 

Despite stepping on a few weeks’ notice to replace AJ’s original opponent (Jarrell Miller, who failed three drug tests), he managed to stun the world.

Ruiz literally battered the champ, dropped him four times, and created one of the most viral upsets in modern boxing.

Biggest Super Bowl upset: Tom Brady’s Patriots Stun St. Louis Rams

Super Bowl XXXVI delivered one of the NFL’s greatest shocks, the night the unstoppable St. Louis Rams were finally stopped.

The St. Louis Rams were a real dream team at the time, led by several future Hall of Famers: Kurt Warner (quarterback), Isaac Bruce (wide receiver), and Marshall Faulk (running back).

Knowing that, it’s no surprise that they came to the Super Bowl with a 14–2 record, and everyone expected them to get hold of the Lombardi Trophy with zero problems.

But the Patriots had other plans. Coach Bill Belichick figured out a way to slow down the St. Louis Rams’ attack. 

Plus, young quarterback Tom Brady put on an offensive masterclass that may never be replicated.

Brady, calm beyond his years, engineered the defining drive of the game. It culminated with placekicker Adam Vinatieri sealing the upset with a field goal in the last second of the fourth quarter.

Brady won the Super Bowl Most Valuable Player (MVP) award, and the game marked the birth of the Patriots’ dynasty.

*image courtesy of Shutterstock

Other NFL & College Football Upsets

18-point Underdogs NY Jets Win Super Bowl III

The biggest underdog to win the Super Bowl was the New York Jets, who did it in 1969. They entered the Championship Game as 18-point underdogs, but then stunned the Baltimore Colts 16–7.

NY Giants Take Down Tom Brady’s Pats in Super Bowl XLII

Fast-forward to Super Bowl XLII and you get another classic: the New York Giants bringing down the unbeaten New England Patriots in one of the NFL’s greatest ever ambushes.

The New York Giants defeated the New England Patriots' perfect 18-0 season in Super Bowl XLII, preventing them from being recognised as the only 19-0 champions in NFL history.

App State Pulls the Impossible Against Michigan

College sports? Even wilder. One of the best examples is Appalachian State’s shock win over Michigan in the NCAA Division I in 2007.

The reason this game is still discussed today is that it marked the first time an FCS school defeated a ranked FBS opponent.

App State’s feat is still talked about like folklore, but that same year, college football saw another major surprise.

41-Point Underdogs? No Problem for Stanford

Stanford rocked USC 24–23, which may not seem like a big win. Sure, it’s always nice to beat a sporting nemesis, and these two have been rivals since 1905.

However, their 2007 game was special for another reason. Before the match started, the boys from California were seen as 41-point underdogs.

USC’s players did well until the final quarter, in which their defence conceded 17 points in total. The crucial moment happened when Stanford’s wide receiver Mark Bradford delivered the match-winning TD with just 48 seconds remaining.

Basketball’s Biggest Surprise: Detroit Pistons Beat LA Lakers

The Detroit Pistons’ 2004 NBA Finals win over the Los Angeles Lakers remains one of basketball’s greatest upsets, a result that still feels impossible on paper.

The Lakers rolled into the Finals as overwhelming favourites, boasting a stack of basketball legends like Kobe Bryant, Shaquille O’Neal, Gary Payton, and Karl Malone. 

Everyone expected this to be a coronation of new NBA kings. But the Pistons didn’t buy the script. 

Powered by a no-ego lineup featuring Chauncey Billups, Ben Wallace, Rasheed Wallace, and Rip Hamilton, Detroit smothered the Lakers’ offense and controlled the series from start to finish.

The result? A stunning 4–1 victory that shattered expectations, embarrassed the “superteam,” and cemented the Pistons as one of the toughest underdog champions in NBA history.

Other Major Surprises in Basketball History

Cleveland’s 3–1 Resurrection That Shook the NBA

Basketball experienced its own earthquake in 2016 when the Cleveland Cavaliers became the first team in NBA Finals history to overcome a 3–1 deficit and win the title.

Villanova’s Perfect Night in 1985

The NCAA has delivered some of the biggest “no way this is happening” moments in sports, and the 1985 Villanova Wildcats sit right at the top of that list.

The eighth-seeded Wildcats weren’t really supposed to survive the first weekend, let alone beat the powerhouse Georgetown Hoyas in the final game of the NCAA tournament.

Yet, they played a near-perfect game, producing one of the greatest upsets in the history of American college sports.

UMBC Becomes the First 16-seed to Beat a No. 1 Seed

Fast-forward to 21st-century March Madness, and you get UMBC pulling off a shock that felt just as unreal. The Retrievers from the University of Maryland became the first 16 seed to defeat a No. 1 seed in NCAA tournament history.

This happened in 2018, when they outclassed the heavily favoured Virginia by 20 points. The final score was 74–54.

FDU’s Giant-Killing Night in 2023

Five years after UMBC beat a No. 1 seed, Fairleigh Dickinson University did the same. It was a close game that FDU won 63–58, with fans biting their nails until the very last second.

The main reason this win is historic, however, is that FDU were 23.5-point underdogs in the bookies' eyes ahead of the game.

Biggest Upset in Baseball History: St. Louis Cardinals Win the 2011 World Series

The St. Louis Cardinals were given odds of 999.00 to win the 2011 World Series, but they rallied late in the season and went on to secure the championship.

With just 83 regular-season wins, nobody blamed the bookmakers. They looked like play-off fillers, not future champions.

But once October arrived, they morphed into a wrecking ball. Powered by Albert Pujols and an instinct for clutch pitching, they bulldozed through the bracket.

Their proudest moment came in the World Series, where they stunned the heavily favoured Texas Rangers.

No team with fewer than 85 wins had ever lifted the trophy until the St. Louis Cardinals ripped up the rulebook.

*image courtesy of Shutterstock

Other Major Upsets in Baseball

Texas Rangers Upset the New York Yankees in the 2010 ALCS

In 2010, the Texas Rangers entered the series with the New York Yankees as clear underdogs. 

Yet behind Josh Hamilton, Nelson Cruz, and a breakout pitching staff, the Rangers stunned the Yankees 4–2 to reach their first World Series in franchise history.

1990 Cincinnati Reds Sweep the Oakland Athletics in the World Series

Two decades earlier, the Cincinnati Reds did something similar against the Oakland Athletics.

The A’s were a dominant powerhouse: back-to-back AL champions, stacked with stars like Rickey Henderson, José Canseco, and Mark McGwire.

The Reds, meanwhile, were solid but unfancied. Then came the shock: Cincinnati didn’t just beat Oakland; they swept them 4–0 to win the championship.

“Miracle Mets” Win the 1969 World Series

In 1969, the “Miracle Mets” won their first World Series. That year, they went from perennial doormats to World Series champions in a single, surreal season.

They stunned the powerhouse Baltimore Orioles and flipped the baseball world on its head, proving that even the biggest long shots can rewrite history when everything suddenly clicks.

More Cinderella Stories Worth Mentioning

Upsets don’t belong only to the world’s most popular sports like football and basketball; they strike in every corner of sport, often without the spotlight they deserve.

From overlooked teams shocking champions to tiny clubs toppling giants, these Cinderella stories remind us that no favourite is ever truly safe.

Here are a few more incredible underdog moments worth mentioning.

Miracle on Ice at Lake Placid (1980 Winter Olympics)

What happened at Lake Placid in 1980 remains one of the purest underdog moments at the Winter Olympics, the kind that still gives you chills.

A group of American college kids got all the way to the medal round. Their eyes were on the gold medal, but a huge obstacle stood in front of them.

The obstacle in question was the seemingly invincible Soviet Union, a machine that had dominated international hockey for years.

Nobody gave Team USA a chance; the Soviet team was seen as favourites that could not possibly fail. But in Lake Placid, they fought, believed, and stunned the world with a 4–3 win.

After that, the Americans went on to beat Finland 4–2, thus securing gold for their nation.

South Africa Wins the 1995 Rugby World Cup

South Africa’s 1995 Rugby World Cup triumph is the kind of upset that becomes national mythology. 

The Springboks, newly returned to international sport after apartheid, weren’t expected to outmuscle the mighty All Blacks in the final, especially with Jonah Lomu steamrolling everyone in sight.

But in Johannesburg, South Africa delivered a defensive masterpiece, matched New Zealand’s physicality, and edged a dramatic 15–12 win.

It became a unifying moment for a nation, capped by Nelson Mandela handing the trophy to captain Francois Pienaar in one of sport’s most iconic images.

Rich Strike Triumphs at Churchill Downs in 2022

Rich Strike’s victory at the 2022 Kentucky Derby is one of horse racing’s ultimate “you’ve got to be kidding me” upsets. 

Entering the biggest event in horse racing as an 80.00 long shot, he wasn’t even supposed to be in the field until a last-minute scratch opened the door.

Then, out of nowhere, Rich Strike produced a jaw-dropping late surge at Churchill Downs, weaving through the pack and stunning every favourite on the board.

It was a pure Cinderella moment: a late entry, a tiny stable, and a comeback nobody saw coming.

Y.E. Yang Defeats Tiger Woods in the Biggest Upset in Golf History

Y.E. Yang’s win over Tiger Woods at the 2009 PGA Championship is still one of the greatest shocks in this sport's history. 

Before that, Tiger had never lost a major when leading after 54 holes. Yang, ranked outside the top 100, wasn’t supposed to be the guy to break that streak. 

But on the final day, he outplayed the most dominant golfer of the era, capped by an unforgettable approach shot over the trees on 18.

Yang held his nerve, Tiger slipped, and golf witnessed a true underdog ripping up the script and claiming a historic major.

Rulon Gardner Becomes an Olympic Gold Medallist in 2000

Known as “The Experiment,” Aleksandr Karelin wasn’t an ordinary wrestler. 

Representing the Soviet Union (and later the Unified Team), he was widely considered the GOAT of Greco-Roman wrestling, especially after winning three Olympic gold medals.

Karelin crushed everyone for over a decade, going 13 years without giving up a single point. With such a resume, he arrived at the 2000 Sydney Olympics as the biggest favourite in wrestling history.

The shock came when American underdog Rulon Gardner defeated the “unbeatable” Karelin. 

Dubbed the “miracle on the mat,” his feat remains one of the biggest upsets in combat sports.

Honourable Mention: 151.00 Underdog Becomes POTUS in 2016

In addition to sports, the world of politics has also produced some massive upsets. Arguably, the biggest came in 2016, when Donald Trump won his first term as President of the United States.

Ahead of the election, even the most optimistic MAGA supporters thought their candidate had only a slim chance. Betting sites were even harsher, with some offering odds as long as 151.00 on Trump beating Hillary Clinton on election night.

In mathematical terms, that means oddsmakers gave Trump roughly a 0.7% chance of reaching the Oval Office.

A Democratic landslide seemed inevitable, and one Irish online sportsbook even went so far as to pay out early on Hillary backers. But, oh boy, were they wrong.

The sportsbook ended up losing more than $4,000,000, Trump walked into the White House, and the rest is history.

Not only did the Republican candidate win the presidency, but he’s still the boss in the White House.

And he’s planning to host a UFC White House event on the South Lawn in 2026.

Underdogs Keep Sports (and Sports Betting) Alive

Upsets are what keep sports alive. They bring out the drama, the disbelief, the “no way that just happened” moments.

And if you're ready to chase the next big surprise, you’ll find every one of these chaos-filled sports waiting for you at Gamdom sportsbook. 

After reading our blog about the greatest upsets in sports history, you know where to look for another surprise.

Individual sports like boxing and golf are gold mines for shocks, but team sports aren’t trailing much behind either. 

They produce their own madness too: just think of Leicester’s 5000.00 miracle.

Bet on Some Longshots at Gamdom Now!