The NBA Finals follows a best-of-seven format, which means that the better team can still win it despite one or two losses along the way. In most cases, the favorites do put together the performances expected from them and go on to claim the coveted trophy. On rare occasions, though, underdogs stun the basketball community to clinch the NBA title.All-time NBA Finals biggest upsetsIn this article, we will take a deep dive into NBA history and bring you the 5 biggest upsets that have happened in NBA Finals history .1968-69 Boston Celtics and Los Angeles LakersNBA Finals Game 1: Boston Celtics v Los Angeles LakersIt is strange to peg the Boston Celtics as underdogs because they were a dominant force in the 1960s. They won eight NBA Championships from 1960 t0 1968. However, they had it rough in the 1968-69 season.The majority of the players in that dynasty were not as athletic as they used to be. With a 48-34 regular-season record, it was evident that the Celtics were clearly not the force they once were.Jerry West recorded his #NBAFInals triple-double (42/13/12) vs @Celtics on May 5, 1969 (@Celtics 108 @Lakers 106) pic.twitter.com/aeysDLYMb9— NBA History (@NBAHistory) June 15, 2015The Los Angeles Lakers, on the other hand, had acquired superstar Wilt Chamberlain in the off-season. His addition to an already stacked Lakers roster made them the favorites.It was all going as expected, with the Lakers having secured a 2-0 lead in the Finals. However, the Celtics found their spark and evened the series after winning games 3 and 4. The next two games were split between the two teams, leading to a game 7.The final game was played in Los Angeles, and many thought the home-court advantage will help the Lakers. But the Celtics shocked the entire basketball community by securing a 15-point lead entering the fourth quarter. Despite a relentless effort by the Lakers to complete an inspired comeback they ended up losing the game by 2 points.1994-95 Orlando Magic and Houston Rockets1995 NBA FinalsThe Orlando Magic came into this NBA Finals as the favorite,s with players like Penny Hardaway and Shaquille O'Neal on their roster. Although the Rockets were the defending champions, they were a shadow of their 1993-94 selves, winning only 47 games in the regular season.Hakeem (35 PTS & 15 REB) shut Orlando down 😤Magic vs. Rockets, 1995 NBA Finals Game 4 - 1:30pm ET on NBA TV! pic.twitter.com/CPPb7tHK0N— NBA TV (@NBATV) June 22, 2020But Hakeem Olajuwon dominated the Finals and bullied Shaquille in the paint. Inexperience made the Magic lose a great advantage in Game 1.The Olajuwon-led Rockets continued to dominate game after game, eventually sweeping past the young Orlando Magic team.2003-04 Detroit Pistons and the Los Angeles LakersThe Lakers dominated the early 2000s era, winning two out of three NBA Finals since 2000. The inability of the team to win the 2002-03 championship led to the acquisition of Karl Malone and Gary Payton.Detroit Pistons v Los Angeles LakersWith the presence of Shaquille O'Neal, Kobe Bryant and the two new signings, the Lakers were huge favorites. But the Pistons, who had no superstar on their roster, managed to clinch the championship in only five games. The reason this is ranked as one of the biggest upsets is because the very offensive-minded Lakers were held to an average of 81.8 PPG throughout the series.2010-11 Dallas Mavericks and Miami HeatCan’t forget when Dirk and the @dallasmavs rallied from a 15-PT deficit in the 4th QTR! 👏Game 2 of the 2011 NBA Finals - 11am ET on NBA TV! pic.twitter.com/fqrNBcLGvi— NBA TV (@NBATV) March 30, 2020The Miami Heat had LeBron James, Dwayne Wade and Chris Bosh on their roster. With all three healthy and fit, the Dallas Mavericks seemed to stand no chance. The Mavericks had some veteran superstars but were not expected to keep up with the physicality of the young Heat team.Miami Heat v Dallas Mavericks - Game FiveAs expected, the Heat got off to a flying start, winning game 1. The Heat managed to blow a 15-point lead in game 2 with just 7 minutes left in the fourth quarter. The Dirk Nowitzki-led Mavericks sealed the deal in game 6, completing one of the biggest upsets in NBA history. It was another NBA Finals where experience won over athleticism.2015-16 Golden State Warriors and Cleveland Cavaliers2016 NBA Finals - Game SevenStephen Curry won the 2015-16 MVP title by a unanimous vote after leading the Warriors to a 73-9 regular-season record. Going into the playoffs, the Warriors were expected to decimate the Cleveland Cavaliers, who had only LeBron James and Kyrie Irving as star players.It was a great start for the Warriors, who secured a 2-0 lead. The Cavaliers won game 3 but were again dominated in game 4. Everyone expected the Warriors to close out the series in game 5, but LeBron and Kyrie had plans of their own. Both recorded 41 points, and they had an opportunity to tie the series in game 6 in Cleveland.The 2015 NBA Finals had it all 🍿 pic.twitter.com/aOxjb1eZcd— ESPN (@espn) May 13, 2020A block from LeBron and pin-point accuracy by Kyrie from beyond the arc had the Cavaliers going ahead late in the game. The Warriors couldn't answer, resulting in Cleveland winning the first-ever NBA championship in the franchise's history.