TORONTO (Reuters) - The Toronto Raptors lost 115-104 to the Boston Celtics in their first game without injured All-Star Chris Bosh Wednesday, loosening their grip on the eighth and final Eastern Conference playoff spot.

In the absence of big man Bosh, who suffered a face injury against the Cleveland Cavaliers 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.

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.

(Reporting by Jahmal Corner in Los Angeles, editing by Nick Mulvenney)