The Celtics jumped out to a sizeable lead, survived a late Miami push, and held on for a 101-91 win in Game 3 of the Eastern Conference finals.
Kevin Garnett had 24 points and 11 rebounds and Paul Pierce scored 23 for Boston, which led by as many as 24 in the fourth quarter and now trails 2-1 in the best-of-seven series.
Rajon Rondo, who scored a career-high 44 points in Wednesday's overtime loss, finished with 21 points and 10 assists. His final basket came in the form of a coast-to-coast layup after the had Heat pulled within eight late in regulation.
"Our goal was to win by any means necessary," said Rondo. "We needed to get the win. I just wanted to sacrifice and do the things for my teammates to get the lead, keep the lead and just run the show."
LeBron James had 34 points, eight rebounds and five assists, while Dwyane Wade scored 18 for Miami.
Game 4 is scheduled for Sunday in Boston.
Mike Miller scored nine of his 11 points in the fourth quarter and hit consecutive threes during a 15-2 Miami push which made for a tense finish at TD Garden.
Wade capped the surge with a slam and Mario Chalmers countered buckets by Garnett and Rondo with five quick points, converting a three-point play after a baseline floater to make it 95-87.
It was still an eight-point game when Ray Allen corralled a Wade miss and gave the ball to Rondo, who dribbled the length of the floor and finished a layup with 1:39 to play.
Garnett drained a 20-foot baseline jumper in the final minute to seal the win.
"(It was a) desperation game, to be honest," said Garnett. "And we played like it too. You don't want to be down 3-0 to a team like this."
James scored more points in the first quarter -- 16 -- than the entire Miami team did in the second -- 14.
His final basket of the first gave the Heat a 28-22 lead, but the Celtics scored eight straight to end the frame. Keyon Dooling blocked James and coasted in for a go-ahead layup and Garnett made a free throw in the closing seconds for a 30-28 Boston lead.
The Celtics opened the second with seven straight points -- six from Garnett -- and capitalized on Miami's ineffective offensive play. James went 2-of-4 in the quarter but the Heat shot just 27.8 percent as a team and Allen drained a three-pointer in the final minute to give Boston a 55-42 halftime lead.
While Miami's struggles defined the second quarter, Boston's offensive efficiency proved the story in the third. Garnett had eight points, Rondo had seven and Pierce had six. The Celtics shot 57.9 percent from the field in the frame and got five points from Marquis Daniels.
It was 85-63 entering the fourth after Pierce's trey at the buzzer.
"They got us tonight," said Heat coach Erik Spoelstra. "We got off to a pretty good start. The reserves came into the game and really knocked us back on our heels. And from that point on we were playing catch-up, it seemed like, the whole night. We couldn't get over the hump."
Only 14 teams in NBA history have come back from an 0-2 deficit to win a best- of-seven series. The Celtics haven't accomplished the feat since 1969...Allen had 10 points...Entering the game, the Heat were 9-0 in these playoffs when scoring at least 90 points.