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The first-round series between the Milwaukee Bucks and Miami Heat took another stunning turn on Monday night when Jimmy Butler poured in a career-high 56 points and the Heat pulled off a 14-point fourth-quarter comeback in Game 4 to take a 3-1 lead. 

All of a sudden, the Heat are just one win away from eliminating a Bucks team that won 58 games in the regular season and earned the No. 1 overall seed in the playoffs. That is certainly no guarantee now that Giannis Antetokounmpo has returned from his back injury, but with Butler playing at this level the Heat have a real chance to make history. 

If the Heat complete the upset, they'll become only the sixth No. 8 seed to win a first-round series since the league expanded the playoffs to 16 teams during the 1983-84 season, and the fourth to do so in a best-of-seven matchup. In addition, they would become the first team to be on both sides of such an upset; they lost as the No. 1 seed in 1999. 

With the Heat on the verge of a historic achievement, here's a look back at the previous No. 8 seeds to pull off the feat. 

1994: Denver Nuggets over Seattle SuperSonics, 3-2

It took a decade for the first No. 8 seed to win a series, and the Nuggets did so in the most dramatic fashion possible. They fell down 0-2 to a SuperSonics group that had won 63 games and would go on to make the Finals a few years later, and lost both games by double digits. The Sonics advancing seemed like just a formality at that point. 

Instead, the Nuggets shot 60 percent from a field in a dominant Game 3 win at home, then stole Game 4 in overtime despite shooting just 36.9% from the field. Even then, the consensus was the Sonics would take care of business in Game 5 in Seattle, where they went 37-4 that season. Not so; the Nuggets prevailed in overtime, 98-94, thanks to eight points, 15 rebounds and eight blocks from Dikembe Mutombo. 

1999: New York Knicks over Miami Heat, 3-2

During the lockout-shortened season in 1999, the Heat went 33-17 and won a three-team tiebreaker for the No. 1 seed. While the circumstances were unique in this postseason, the Heat were still expected to win the series, especially with home-court advantage. 

The Knicks, though, set the tone with a 20-point win in Game 1. From there, the teams traded double-digit wins until the winner-take-all Game 5, which went down to the wire. With the Knicks trailing by one in the closing seconds, Allan Houston put up a runner which hit the front of the rim, bounced off the backboard and fell through the net to win the series. 

The Knicks ended up becoming the first, and still only, No. 8 seed to advance to the Finals, where they fell to the San Antonio Spurs in five games. 

2007: Golden State Warriors over Dallas Mavericks, 4-2

Coming off a Finals defeat in 2006, the Dallas Mavericks won 67 games in 2007, which was the best record in the league by six games and is still tied for the seventh-best regular season record all-time. While they were a title favorite, they did have a potentially tricky first-round matchup against a Golden State Warriors team that had won 16 of its final 21 games down the stretch and had handed the Mavs two of their biggest losses in the regular season. 

As it turned out, Baron Davis and Co. really did have the Mavs' number. The Warriors won Game 1 on the road, then took all of their home games thanks to a raucous Oracle Arena crowd. Even more impressive is how easy they made it look; three of their four wins were by double digits, including a 25-point blowout in Game 6. 

The "We Believe" Warriors ended up falling to the Utah Jazz in five games in the second round, but will forever be remembered in the Bay Area. 

2011: Memphis Grizzlies over San Antonio Spurs, 4-2

The Western Conference was incredibly tough in the early 2010s, as evidenced by the fact that the Grizzlies won 46 games and were only the No. 8 seed; that would have been good for the No. 4 seed in the West this season. Still, the Spurs were dominant for much of the regular season en route to 61 wins, and were expecting to challenge for a title. 

Instead, they witnessed the birth of the "Grit-N-Grind" Grizzlies, who simply refused to lose in an extremely narrow series. The Grizzlies won Games 1 and 3 by three points and five of the six games were decided by single digits. This was the first playoff series win for the Grizzlies in franchise history, and the start of their finest era. 

2012: Philadelphia 76ers over Chicago Bulls, 4-2

The early 2010s saw the Chicago Bulls rise to the ranks of title contenders for the first time since Michael Jordan's retirement. With Derrick Rose leading the way, they made it to the Eastern Conference finals in 2011, and earned the No. 1 seed in the East in the lockout-shortened 2012 campaign. 

Heading into the 2012 playoffs, another showdown with the Miami Heat seemed to be on the cards, but Rose tore his ACL in the closing minutes of Game 1 of the Bulls' first-round series against the Philadelphia 76ers. Though the Bulls hung on to win that game, they bowed out in six games and never reached those heights again.