Sports Reference Blog

The 15 Biggest Playoff Upsets in NBA History

Posted by Jonah Gardner on May 19, 2016

The Oklahoma City Thunder shouldn't be here. It's weird to think of a team that won 55 games and boasts 2 of the 5 best players in the league (at least, according to the NBA MVP voting) as an underdog, but the Thunder spent the year in the same conference as two historically dominant teams. There was the San Antonio Spurs, who posted the 7th best point differential of all-time. At the same time, there was the Golden State Warriors who, in case you didn't hear, won a lot of games this season.

Yet the Thunder tore through the Spurs, winning the series in 6, clinching it in a blowout, and perhaps ending then nearly 20-year career of Tim Duncan. Then they followed it up by going to one of the toughest arenas for road teams in the NBA and stealing Game 1 from the 73-win defending champs.

These were both big upsets. Here's a Tweet with a screenshot of Basketball-Reference's playoff odds from April 28, pre-Game 1.

The Spurs had close to a 75% shot at beating the Thunder, going into the series. Similarly, the Warriors' probability of winning the series was over 75% heading into Game 1:

That may still come to pass, but, either way, the Thunder have pulled off one of the biggest upsets in recent memory by beating the Spurs. But how big? Was it one of the biggest of all-time? These are tricky questions but, fortunately, there's a way to quantify the answer.

That way is Simple Rating System, a metric used by Basketball-Reference to measure the strength of a team. SRS considers a team's point differential and the difficulty of its schedule to determine how many points better or worse than average a team played in a given season.

So, for example, this year's Thunder had an SRS of 7.089, meaning they were around 7 points better than the average NBA team. The Spurs' SRS was 10.275. That means the Thunder overcame an SRS gap of 3.186 to win the series.

That gap does break the Top 50 for all-time upsets, but the Thunder were too good for this to be a truly top-tier upset, even given the historic regular season excellence of the Spurs. Here, then, are the 15 biggest upsets in the history of the NBA Playoffs.

One caveat: The list only includes 7-game series. The longer the series, the more difficult it is for a heavy underdog to pull off the upset. So, with apologies to the 1995 Lakers (whose defeat of the Sonics was the 2nd biggest upset overall) and the 1994 Nuggets, among others, you had to win 4 times to make this list.

Oh, and those numbers in parentheses with the teams? They'll be the team's Win-Loss record and SRS. So without further ado, let's look at some upsets!

15. 1995 NBA Playoffs: Houston Rockets (47-35, 2.324) over Orlando Magic (57-25, 6.444). SRS gap = 4.120

Coming in at #15 is the 1995 NBA Finals, a classic showdown between two of the most talented big men to ever play the game. The Rockets may not have had a super impressive regular season, but they did have Hakeem. And not just Hakeem, but Angry, Snubbed for MVP Hakeem. The Dream averaged 32.8 points, 11.5 rebounds, 5.5 assists, 2.0 steals, and 2.0 blocks in that series, too much for the only team to win a playoff series against Michael Jordan's Bulls after 1991 to handle.

14. 2014 NBA Playoffs: Brooklyn Nets (44-38, -1.575) over Toronto Raptors (48-34, 2.554). SRS gap = 4.129

This was a somewhat plodding series between two playoff teams on vastly different trajectories. The Nets were supposed to be a championship contender, having added Paul Pierce and Kevin Garnett to a core that included Deron Williams and Joe Johnson, but they struggled to get through the regular season, just squeaking by with a winning record despite a negative SRS. On the other hand, the Raptors entered the season with their best player, Rudy Gay, widely considered to be a ball-stopper on the floor and a financial albatross off it. A funny thing happened when the Raptors traded him; instead of heading to the lottery, they got better, finishing with the 12th best SRS and home court advantage in the first round.

The series itself wasn't much to speak of (the teams had an average pace of 88.0 and had Effective Field Goal Percentages in the .480-.500 range), but the extensive playoff experience of KG, Pierce, and Johnson won out over the relatively green Raptors.

13. 1971 NBA Playoffs: Baltimore Bullets (42-40, 0.913) over New York Knicks (52-30, 5.049). SRS gap = 4.136

One year removed from the first Finals win in Knicks history, New York had every reason to be confident about a shot at a repeat, with only the middling Bullets standing in the way of a return trip to the championship. However, in a tight seven game series, that included two games decided by two points or less, the Bullets prevailed, making the Knicks wait a couple of years for that second title.

12. 2001 NBA Playoffs: Los Angeles Lakers (56-26, 3.744) over San Antonio Spurs (58-24, 7.919). SRS gap = 4.175

One problem with using regular season SRS to measure team strength is that not every team approaches the regular season the same way. In 2001, the Spurs, as they've done more or less every year under Gregg Popovich, dominated in the regular season, leading the 2000-01 NBA in SRS. The Lakers, on the other hand, were content to cruise. While their records were similar, the Spurs were over 4 points stronger in the regular season.

Yeah, about that. After going 7-0 in the first two rounds, the Lakers swept San Antonio, behind Kobe Bryant's 33 points per game and Shaquille O'Neal's 27 & 13. It turns out when they needed to be, those two were pretty good.

11. 1974 NBA Playoffs: Boston Celtics (56-26, 3.423) over Milwaukee Bucks (59-23, 7.613). SRS gap = 4.190

As you'd expect any team with Kareem Abdul-Jabbar and Oscar Robertson to do, the 1974 Bucks shredded the competition in the regular season and lost just one game on the way to the 1974 Finals. But the Bucks suffered a key injury to Lucius Allen and, despite Kareem averaging 32, could only manage 92 points per game against the Celtics. Smart coaching and a great performance from John Havlicek got the Celtics their first title since Bill Russell's retirement.

10. 1958 NBA Playoffs: St. Louis Hawks (41-31, 0.818) over Boston Celtics (49-23, 5.015). SRS gap = 4.197

This is the highest ranking NBA Finals upset on the list, as a team that was roughly comparable, in terms of SRS, to this year's Trail Blazers managed to take down league MVP Bill Russell and the Boston Celtics in 6. Four of the six games were decided by three points or less, as the Hawks managed to squeak out the series behind Bob Pettit's 29 PPG, 17 RPG performance.

9. 1959 NBA Playoffs: Minneapolis Lakers (33-39, -1.421) over St. Louis Hawks (49-23, 2.889). SRS gap = 4.310

But karma would come for the Hawks one year later. Despite significant regular season improvement in 1959, the Hawks fell in the playoffs to the single worst NBA team to make the list. The 1959 Lakers had an SRS close to the 2016 Chicago Bulls, and fell behind 2-1 in the series, but Elgin Baylor rallied the team to win 3 in a row and end the Hawks' shot at back-to-back titles.

8. 1978 NBA Playoffs: Seattle Supersonics (47-35, 1.484) over Portland Trail Blazers (58-24, 5.916). SRS gap = 4.432

The Trail Blazers are one of a few teams on this list who saw their season derailed by injuries. In this case, it was Bill Walton, who only played in the first two games of the series. Still, that includes a Game 1 that Seattle, whose best player by Win Shares that year was Marvin Webster, stole in Portland. For the Trail Blazers, a title defense that started 50-10 would come to an abrupt, disappointing end.

7. 1973 NBA Playoffs: Golden State Warriors (47-35, 3.123) over Milwaukee Bucks (60-22, 7.842). SRS gap = 4.719

This two-year run by the Bucks, the only team to make this list by getting upset in back-to-back years, is not entirely dissimilar to what the Spurs have been through the last couple of years. Both teams featured an all-timer (Oscar/Tim Duncan) and a young superstar (Kareem/Kawhi Leonard), but had their seasons end in somewhat surprising playoff disappointments two years in a row. Like the Spurs, the Bucks took a 2-1 lead in the series (including a Game 1 blowout win), only to lose 3 straight and exit the playoffs before the Conference Finals.

6. 1986 NBA Playoffs: Houston Rockets (51-31, 2.104) over Los Angeles Lakers (62-20, 6.839). SRS gap = 4.735

13 years later, Kareem would experience another playoff stunner, this time in the role of the aging Hall-of-Famer. This super talented Lakers team, who won titles the year before and the year after, was overwhelmed by a 23-year-old Hakeem Olajuwon, who has 2 of the top 15 all-time upsets to his name.

5. 2013 NBA Playoffs: Memphis Grizzlies (56-26, 4.323) over Oklahoma City Thunder (60-22, 9.148). SRS gap = 4.825

This is another upset caused by an injury, but if your only real memories of the 2013 Grizzlies come from their shellacking at the hands of the Spurs, you might be underrating this team a little bit.  They were the 6th best team in the league in 2013, by SRS, and featured career high years in Win Shares from Marc Gasol and Mike Conley. The Thunder's SRS that year led the league (they were almost 2 points ahead of the Heat), and even without Russell Westbrook, they still had Kevin Durant. Despite the injury, this is still a very impressive upset.

4. 1981 NBA Playoffs: Kansas City Kings (40-42, -0.493) over Phoenix Suns (57-25, 4.830). SRS gap = 5.323

The Suns were the 4th best team in the NBA, and boasted the strongest Defensive Rating in the league that year. But despite the fact that Phoenix outscored the Kings 642-623 in total in this series, the Kings took an early 3-1 lead in the series and managed to nick Game 7 in Arizona, thanks to 23 points in the series clinching game from future Wizards GM Ernie Grunfeld.

3. 1976 NBA Playoffs: Phoenix Suns (42-40, 0.593) over Golden State Warriors (59-23, 6.232). SRS gap = 5.639

If the Thunder defeat the Warriors, it would be a 3.29 point upset, according to SRS, which means it would only be around 60% as shocking as what happened to Golden State the last time they had a title to defend. Against a team that barely played .500 basketball in the regular season and were led by a rookie (Alvan Adams) and a player who had, at that point, never made an All-Star Game (Paul Westphal), the Warriors fell in 7.

If you are looking for a modern comparison for what this would be like, a series from the 2016 NBA Playoffs actually provides a nice parallel. The Suns' SRS is roughly where the Pistons were this year and the Warriors were a point higher than Cleveland. Fortunately for the Warriors, there was no Twitter or First Take in 1976.

2. 2011 NBA Playoffs: Atlanta Hawks (44-38, -1.097) over Orlando Magic (52-30, 4.924). SRS gap = 6.021

The same Magic team that rode hot 3-point shooting to a Finals appearance just two years earlier ended up being undone by their performance behind the arc. Despite a 27 PPG, 15 RPG series from MVP runner-up Dwight Howard, the Hawks managed to shut down his supporting cast. The Magic shot just .262 from 3-point range in the series, and that cold shooting ended up helping a well below-average Hawks team to a shocking First Round win.

ABA Honorable Mention: 1975 ABA Playoffs: Spirits of St. Louis (32-52, -4.020) over New York Nets (58-26, 6.580). SRS gap = 10.6

There were plenty of upsets in ABA history, but this was the biggest. In fact, out of every playoff series in the Basketball-Reference, this was far and away the biggest upset ever. The Nets, featuring Julius Erving and coming off of a strong regular season, didn't just lose to a team with a losing record; they got annihilated. The series only went 5 games and the Spirits won 4 in a row, after dropping Game 1. Despite SRS rating the Nets as 10 points stronger than the Spirits, St. Louis outscored New York by 6 points per game, an almost inexplicable 16-point swing.

1. 2007 NBA Playoffs: Golden State Warriors (42-40, -0.002) over Dallas Mavericks (67-15, 7.279). SRS gap = 7.281

But, if we're sticking to the NBA, then it's the We Believe Warriors who pulled off the biggest playoff upset of all-time. They didn't even need seven games to do it, finishing off the Mavericks, led by 2007 MVP Dirk Nowitzki, in six. This was the sad punctuation mark at the end of a gut-wrenching two year period for the Mavs, following the somewhat controversial loss in the 2006 NBA Finals. The Warriors, an average team in both record and SRS, would go on to win just one more playoff game.

And yet, they're more well-remembered today than the team that eliminated them, the Carlos Boozer/Deron Williams Jazz. So if the Thunder do end up missing out on the Finals, they can look back and take solace in what they've already accomplished. If you can't win a title, upsetting a 67-win team is still a pretty decent path to immortality.

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