Boston Celtics forward Jayson Tatum. Kyle Terada-USA TODAY Sports

The Boston Celtics have reached the NBA Finals, and that’s about the last thing many online sportsbooks wanted to see.

The Celtics went 36-36 last season and lost in the first round of the playoffs. They had a new coach starting this season, and few people saw them as a championship contender. That includes sportsbooks, where the Celtics had 50:1 odds to start the season. Boston’s championship odds went as high as 66:1 when they were 19-22 in January.

According to BetOnline.ag, some savvy bettors saw a talented but underachieving team and laid some futures bets on the Celtics at those great odds.

Boston turned things around in a hurry and quickly became one of the best teams in the East. They earned the No. 2 seed in the conference and just eliminated the Heat in seven games to reach the NBA Finals.

Now, sportsbooks are set to lose money based on either Golden State or Boston winning. And if the underdog Celtics pull off the upset, sportsbooks would owe some real money. BetOnline apparently would stand to lose over a million dollars if Boston wins it all.

Of course, the Celtics would have to really pull off an upset to make that happen, especially when you compare the NBA Finals experience between the teams.

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