Paul Pierce scored 21 points, moving nine behind Hall of Famer Larry Bird for second place on the club’s all-time list, and Ray Allen added 12. Rajon Rondo had 14 assists and reserve Chris Wilcox chipped in with 12 points.
Rudy Gay paced the Grizzlies with 21 points and seven rebounds, and O.J. Mayo scored 15 points for Memphis.
Boston took charge with a 21-7 run early in the fourth quarter that turned a six-point lead to 90-70 on Garnett’s jumper.
Relying on a combination of reserves and two of their usual stars – Garnett and Pierce – the Celtics controlled the glass and outran the Grizzlies for transition baskets.
HEAT 95, RAPTORS 89
In Miami, LeBron James scored 30 points, Dwyane Wade had 25 and the Heat survived a shaky fourth quarter to beat Toronto.
Former Georgia Tech standout Chris Bosh scored 12 points against his former team, which saw a 15-point edge trimmed to three in the final minutes but never surrendered the lead. Mario Chalmers added 11 for Miami.
DeMar DeRozan scored 25 for the Raptors, who got 17 apiece from Jerryd Bayless and Linas Kleiza.
Miami won for the 10th time in its past 12 games and moved within one game of Chicago for the best record in the Eastern Conference.
Kleiza’s 3-pointer with just under 5 minutes left got Toronto within eight, and another 3 from Bayless as the shot clock expired on the next possession cut the Miami lead to 85-80 – the closest the game had been since early in the third quarter.
Toronto missed all but one of its shots over a 7-minute stretch of the third, a span where Miami started with a 55-54 lead and increased it 73-57.