Dion Waiters attempt at a game-tying lay up with :08 left on the clock was blocked by Boston's Brandon Bass to help seal a 103-100 Celtic win. The Cavs had a chance for a game-tying three off at the buzzer, but could not get the shot off in time.
Kyrie Irving scored a game-high 32 in the loss. Jeff Green and Jordan Crawford each had 19 to lead six Boston players with double digits.
The Cavs trailed by 20 points before rallying to make it a game in the fourth quarter.