NBA Playoffs: Biggest Upsets in NBA History
NBA Playoffs: Biggest Upsets in NBA History
Few things in sports feel as electric as a true underdog run. NBA History is a topic every basketball fan eventually falls down a rabbit hole researching, because the postseason has a strange habit of humbling even the most dominant regular-season teams. A 65-win juggernaut can walk into a first-round series and walk out stunned, and that unpredictability is exactly why the playoffs matter more than the standings ever could.
Having followed the league closely across multiple postseasons, one pattern stands out: upsets rarely happen by accident. They are usually the product of an injury at the worst possible time, a role player catching fire for two weeks, or a lower seed that simply matches up better than its record suggests. This article breaks down the biggest upsets in NBA history, explains why they happened, and gives you a clean reference table you can scan in seconds.
What Counts as a Playoff Upset?
Before ranking the biggest upsets in NBA playoff history, it helps to define the term. Most analysts consider a result an upset when a significantly lower-seeded team, usually a No. 7 or No. 8 seed, defeats a No. 1 or No. 2 seed in a best-of-seven or best-of-five series. Since the NBA playoffs expanded to a 16-team format in the 1983-84 season, only a handful of No. 8 seeds have managed to knock out a No. 1 seed, which is exactly why each occurrence gets remembered for decades.
8 Seed vs. No. 1 Seed Upsets
This table captures every documented case of a No. 8 seed beating a No. 1 seed since the 16-team playoff format began, one of the clearest markers of the biggest upsets in NBA history.
| Season | Team (8-Seed) | Beat (1-Seed) | Series Result | Next Round Outcome |
| 1993-94 | Denver Nuggets | Seattle SuperSonics | Won in 5 games | Lost in Round 2 |
| 1998-99 | New York Knicks | Miami Heat | Won in 5 games | Lost in NBA Finals |
| 2006-07 | Golden State Warriors | Dallas Mavericks | Won in 6 games | Lost in Round 2 |
| 2010-11 | Memphis Grizzlies | San Antonio Spurs | Won in 6 games | Lost in Round 2 |
| 2011-12 | Philadelphia 76ers | Chicago Bulls | Won in 6 games | Lost in Round 2 |
| 2022-23 | Miami Heat | Milwaukee Bucks | Won in 5 games | Lost in NBA Finals |
Six No. 8 seeds have taken down a No. 1 seed in NBA playoff history. That scarcity is precisely what makes this list so compelling for anyone researching the biggest upsets in NBA history.
The Five Biggest Upsets in NBA Playoff History, Explained
1. The 2007 “We Believe” Warriors
Starting the season 26-35, then stunned a 67-win Dallas Mavericks team in six games, just a year after Dallas had reached the NBA Finals. Baron Davis and Stephen Jackson led a fast, physical, three-point-happy Warriors squad that simply had Dallas’s number stylistically. This remains one of the most iconic playoff upsets in NBA history because of the win total gap between the two teams.
2. The 2023 Miami Heat Over the Milwaukee Bucks
The Heat became only the sixth No. 8 seed to win a first-round series since the playoffs expanded to 16 teams in 1983-84, and only the fourth to do it in a best-of-seven format. Jimmy Butler averaged an extraordinary 37.6 points per game across the series while Giannis Antetokounmpo battled injury. What made this one of the biggest upsets in NBA playoff history is that Miami did not stop there; the Heat rode that momentum all the way to the NBA Finals.
3. The 1994 Denver Nuggets Over the Seattle SuperSonics
Denver became the first 8-seed to win a playoff series when it knocked off a 63-win Sonics team despite finishing 21 games behind Seattle in the standings. The Nuggets fell behind 2-0 before storming back, a comeback that basketball historians still cite when discussing the biggest upsets in NBA history.
4. The 1999 New York Knicks Over the Miami Heat
New York only finished six games behind Miami during that lockout-shortened season, so the upset was not a complete shock, but the Knicks’ run afterward turned it into a legendary story. New York became the first No. 8 seed ever to reach the NBA Finals, a feat that has never been repeated.
5. The 2011 Memphis Grizzlies Over the San Antonio Spurs
Memphis was a strong 8-seed with 46 wins, yet San Antonio’s early exit under Gregg Popovich still shocked the basketball world. This series, decided largely by grind-it-out defense, launched the “Grit and Grind” era in Memphis and stands as one of the most physically dominant upsets in NBA playoff history.
Upsets Beyond the No. 1 vs. No. 8 Matchup
Not every major upset in NBA playoff history involves the top seed. Several lower-profile series still rank among the biggest upsets in NBA history because of how far the favorite fell short of expectations:
● 2012 Philadelphia 76ers over Chicago Bulls Derrick Rose tore his ACL in Game 1, and Philadelphia capitalized to end Chicago’s title hopes.
● 1995 Houston Rockets’ title run Houston entered the playoffs as the No. 6 seed and still won the championship, arguably the most complete underdog run in league history.
● 2023 Boston Celtics almost losing a 3-0 series lead while not a full elimination, Miami’s comeback attempt against Boston in the same postseason nearly created an even bigger upset.
Why These Upsets Matter to Fans and Analysts
Studying the biggest upsets in NBA history is not just nostalgia. It teaches real lessons about roster construction, playoff matchups, and momentum. Lower seeds that win usually share three traits: elite perimeter defense, a hot-shooting guard, and a coach willing to make unconventional adjustments. Teams and fans who understand these patterns can better predict which underdog might pull off the next shocking result. Anyone who has watched several postseasons in a row starts recognizing the signs early, like a star player suddenly elevating his scoring average or a role player who cannot miss from three-point range.
Frequently Asked Questions
1. What is the biggest upset in NBA playoff history?
Most analysts consider the 2007 Golden State Warriors over the 67-win Dallas Mavericks the biggest upset, due to the massive gap in regular-season records.
2. How many times has a No. 8 seed beaten a No. 1 seed in the NBA playoffs?
Six times since the 16-team playoff format began in 1983-84: Denver (1994), New York (1999), Golden State (2007), Memphis (2011), Philadelphia (2012), and Miami (2023).
3. Has a No. 8 seed ever won the NBA championship?
No. The furthest a No. 8 seed has gone is the NBA Finals, achieved by the 1999 Knicks and the 2023 Heat, but neither won the title.
4. Why do NBA playoff upsets happen so rarely?
Best-of-seven series reward consistency and depth, which usually favors higher seeds. Upsets typically require an injury to a star player, a red-hot shooting stretch, or a favorable stylistic matchup.
5. What was the most recent big NBA playoff upset?
The 2023 Miami Heat’s first-round win over the No. 1 Milwaukee Bucks is the most recent example, and Miami advanced all the way to the NBA Finals that year.
Final Thoughts
The history of NBA playoff upsets proves that seeding is only a prediction, not a guarantee. Whether it is the 2007 Warriors stunning Dallas or the 2023 Heat toppling Milwaukee, the biggest upsets in NBA history remind fans why the postseason remains the most watchable stretch of the basketball calendar. As the play-in tournament creates more paths for lower seeds to sneak into the bracket, do not be surprised if the next entry on this list is written sooner than expected.
