In the absence of big man Bosh, who suffered a face injury against the Cleveland Cavaliers on Tuesday, the Raptors (38-40) faded late in the game to see their lead over the Chicago Bulls cut to half a game with four to play.
“I think this is the moment we need everybody together,” Toronto guard Jose Calderon told reporters.
Rajon Rondo scored 21 and Paul Pierce added 20 to lead the Celtics (49-29), who moved into a tie with the Atlanta Hawks for third place in the East.
The game was tied at 76-76 in the third quarter but Boston ended the period with six straight points and took that momentum into the fourth, where they clinched what was just a second win in six contests.
In the final quarter, the Celtics’ sharpshooters came up big. Ray Allen tallied 10 of his 18 points while Michael Finley put up 11 of his 14 off the bench to seal the win.
“Our shooting won the game for us tonight,” said Boston coach Doc Rivers.
“When Ray and Michael get it going at the same time and they’re both on the floor, that makes us really good because we can still pound the ball down low and affect the other team’s ability to take the low-post game away.”
Sonny Weems scored a career-high 21 points for the Raptors to combine with Andrea Bargnani, Antoine Wright and Jarrett Jack who all finished with 17.
Toronto stayed close for most of the night but missed Bosh’s presence inside. Bosh leads Toronto with 24 points per game and 10.8 rebounds.
Bosh, who underwent surgery to repair a displaced nasal fracture on Wednesday, could miss the rest of the regular season, making things tricky for the Raptors in their final push for the postseason.
Raptors forward Hedo Turkoglu was also injured on Wednesday, leaving the game in the first quarter after hurting his nose in a collision with Tony Allen.
