Boston raced to a quick 12-2 lead and never trailed. The lead was 37-20 at the end of the first period, 51-37 at the half and 91-65 heading to the fourth after three-pointers by Allen and James Posey.

Paul Pierce had 19 points, five assists and four rebounds. Kevin Garnett had 17 points with eight rebounds.

Posey scored 15 off the bench and Kendrick Perkins added 13 points with 11 rebounds for the Celtics, who have clinched an Eastern Conference playoff berth.

Garnett became the 32nd player in NBA history to score at least 20,000 points in his career.

Hakim Warrick led Memphis with 15 points and five rebounds. Rudy Gay scored 13, Mike Conley 11, and Darko Milicic had 10 points and four rebounds for the Grizzlies, who have lost nine of 10.