1. 1968-69 Boston Celtics
This has been one of the biggest upsets in NBA history. The Boston Celtics, the fourth place team in the Eastern Conference that season, beat the Los Angeles Lakers in seven games after losing the first two on the road.
This was the last championship of Bill Russell's career, and the Celtics managed to defeat a team that had Elgin Baylor, Wilt Chamberlain and Jerry West on their roster.
West had a tremendous Game 7, ending with a triple-double (42 points, 13 rebounds, 12 assists), and he even was named the NBA Finals MVP. As of 2018, he is the only player named the NBA Finals MVP who was on a losing team. This was also the first year that the award was given.
The Celtics won back-to-back titles and became the first team to overcome a 0-2 deficit.