Miracles Do Happen: Top 4 Biggest Upsets in Sports History

When March Madness rolls around every year, sports fans take time filling out NCAA Tournament brackets in hopes of correctly picking the Final Four. Then there’s that rare occasion where the No. 1 seed that many picked to win it all, gets knocked out by a 25-point underdog. It means before March Madness’ opening weekend ends, the office pool bracket gets tossed.

Of course there have been much bigger upsets. When talking about the greatest upset in Winter Olympics history, nobody hesitates mentioning the United States ice hockey defeating the Soviet Union in 1980. If you weren’t around to see it, do a Google search for the Miracle on Ice.  

Today, these underdog moments are magnified even more thanks to legal online sports betting.  Bettors end up being the big winners from backing a huge underdog that oddsmakers typically give under a 20% chance of winning. 

But what are the biggest upsets ever? 

Here’s a closer look at what we consider the four biggest upsets in sports history.

What Makes an Upset Truly Historic?

If we are looking at things from a sports betting perspective, there are small upsets such as the Miami Dolphins, who are a +3.5 underdog, defeat the Las Vegas Raiders during NFL Week 1. However, the truly historic upsets are the ones nobody sees coming. Would anybody in their right mind take the Cleveland Browns to win the Super Bowl  with +20000 odds? That’s an implied probability of .50%. 

If for some crazy reason it does actually happen, it could easily be added to the list of historic upsets that leave sports fans across the country totally stunned. 

Team USA’s 1980 “Miracle on Ice” victory over the Soviets was such an epic moment that it was still talked about during the 2026 Winter Olympics. 

We’re talking about historical events with pre-event betting odds that heavily leaned toward a completely different outcome.

Ranking The Four Biggest Upsets In Sports History

4. New York Giants vs. New England Patriots, Super Bowl XLII

Some could argue that Eli Manning had Tom Brady’s number. Looking back at the New England Patriots' nearly perfect 2007 season, they entered Super Bowl XLII a perfect 18-0, and were on the verge of becoming the first 19-0 team in NFL history. New England opened as a 14-point favorite and remained a 12.5-point favorite at kickoff. The Giants moneyline, or odds of an outright victory, were +475 or an implied probability of 17.39%. 

When the G-Men won the game 17-14, it ended up being an extremely expensive night for Las Vegas sportsbooks that  lost a reported $2.6 million. 

This wasn’t the first time the younger Manning brother spoiled the Pats Super Bowl dreams. Four years later, the Giants won again, 21-17. Even with those two losses, New England still won six Super Bowls and built one of the greatest sports dynasties ever.

3. Appalachian State vs. Michigan, 2007

Even though Appalachian State opened the 2007 as the two-time defending FCS champion, there was no way the college football betting world envisioned that the team had even a fighting chance of upsetting the No. 5 Michigan Wolverines, especially with the game being played at the Big House. Oddsmakers had the Mountaineers as a 33.5-point underdog. 

Well, there is a first time for everything. App State went ahead 34-32 via Julian Rauch’s 24-yard field goal that ended up being the game winner. With 26 seconds left. Michigan would get a chance to win the game by 1, but Jason Gingell's 37-yard field goal attempt was blocked..   

This one earns a spot on the list because it was the first time an FCS team upset a highly ranked FBS opponent.

2. Buster Douglas vs. Mike Tyson, 1990

Buster who? When “Iron” Mike Tyson stepped into the ring against James “Buster” Douglas on February 11, 1990, his record was 37-0 with 33 knockouts. Even though Douglas was the seventh ranked heavyweight by THE RING magazine at the time, he wasn’t in Tyson’s league. With Tyson listed as a 42-1 favorite, there was less than a 3% implied probability of Douglas shocking the Tokyo crowd. 

The possibility of Tyson scoring a first round knockout seemed like a more likely scenario being that 17 of his first 37 bouts played out that way. On this night, Douglas was the better, more aggressive fighter, with 198 power punches compared to Tyson’s 138. Then in the 1oth round, the unthinkable happened - Douglas knocked out Tyson. This underdog story didn’t have a long shelf life asDouglas’ pro fighting career came to an end in October 1990 when he was knocked out by Evander Holyfield in the third round. He retired with a 38-6 record.  

1. Miracle on Ice:  USA vs. Soviet Union, 1980 Olympics

You don’t even have to be an ice hockey fan to appreciate how big a deal it was for Team USA to upset the Soviet Union, 4-3, in the 1980 Winter Olympics medal round. Al Michaels’ “Do you believe in miracles?" line during the game’s final seconds is still one of the most memorable calls in sports broadcasting history. 

Even with the Americans being the home team, the matchup tilted heavily in the Soviet Union’s favor. Between 1960 and the 1980 Olympics, the Russians won all 12 contests against the Americans. The USSR was the more experienced, dominant team while Team USA consisted of college players. Some might recall that a week before the 1980 Winter Olympics began, these teams played in an exhibition at Madison Square Garden that the Soviet Union won easily, 10-3. 

When these Super Power nations met again in Lake Placid, the Soviets were still considered heavy favorites. Granted the game took place during the sports betting stone age when iPhone, Android, and mobile sports betting apps were all  foreign words. 

The game that doesn’t get talked about anywhere nearly as much was the 1980 gold medal match against Finland that the Americans won 4-2 thanks to three unanswered third period goals.

Why Betting Odds Matter

All of the highlighted upsets pre-date the Professional and Amateur Sports Protection Act (PASPA) act being overturned. While sports betting was legal in Nevada, sports bettors weren’t scrolling through odds on mobile devices trying to decide which of these underdogs was worth backing. 

Today, we use our sportsbook app of choice to analyze moneyline odds, points spreads, and even futures markets. For example, the Washington Commanders and Indianapolis Colts both have +6000 Super Bowl odds. Diehard fans might see this as a low risk, high reward situation being that a winning $100 wager on either team will result in a $600 profit. 

The Most Improbable Upset of Them All

There are several more major upsets that were seriously considered, including when No. 16 University of Maryland Baltimore County upset No. 1 Virginia in the first round of the 2018 NCAA Tournament. UMBC took the court as a +20.5-point underdog. 

However, nearly 50 years later, it’s hard to argue against the United States 1980 Olympic Games victory over the Soviet Union being the greatest and improbable sports upset of all time. Everything pointed to a major mismatch, yet the Americans absolutely defied the odds.