If the Celtics wanted to keep their hopes of an 18th title alive this season, it had to start with a win on Saturday night.
Boston, which now trails the series 2-1 following Sunday's win, jumped out to a 27-21 lead after the first quarter, but Miami outscored the Celtics, 25-17 in the second quarter.
The third quarter was key for the Celtics, who outscored Miami 28-15. Boston kept up the pace in the fourth and final quarter, putting up 25 points while holding the Heat to 20 points.
Ray Allen scored 15 points and Delonte West added 11 points off the bench for Boston. West played extended minutes, as starting point guard Rajon Rondo (six points, 11 assists) dislocated his elbow in the third quarter, but he did return.
Dwayne Wade scored 23 points to pace the Heat, who were held to 42.5 percent shooting. LeBron James finished with 15 points on 6-of-16 shooting and Mario Chalmers paced the Heat bench with 17 points. Joel Anthony had a solid night off the bench for Miami, amassing 12 points and 11 rebounds.