BOSTON (AP) -- The Boston Celtics overcame a very imperfect fourth quarter to preserve their perfect season.
Paul Pierce made the go-ahead layup with 25 seconds left after Boston squandered a 15-point, fourth-quarter lead and the Celtics held on to beat the Miami Heat 92-91 on Friday night to improve their record to 8-0.
Kevin Garnett had 26 points and 11 rebounds for Boston, which is off to its best start since the 1972-73 team led by John Havlicek and Dave Cowens won its first 10.
"We're nowhere near where we want to be," said Pierce, who scored 12 points despite a strain in his back that almost forced coach Doc Rivers to scratch him from the game. "We're far from a perfect team. We definitely have weaknesses right now."
Dwyane Wade, making his first start after offseason knee and shoulder surgery, scored 23 for Miami but also missed five free throws in the game -- and the potential game-winning basket in the final seconds.
The Heat took a 91-90 lead on Udonis Haslem's free throw with 33 seconds left, but Pierce muscled his way to the basket to give the Celtics back the lead. Wade dribbled out most of the shot clock before putting his shot off the back of the rim.
"I'm a gamer, man. Give it to me 10 times and I'll do it 10 more times," said Wade, who scored 23 and cracked a smile before squaring up against ex-teammate James Posey for the final shot. "There was a lot of stuff going through my head: Being out six months, my second game back I had an opportunity to win the game against the best team in the league, record-wise, in the Boston Garden."
Posey said he was eager to guard Wade, who came off the bench and played 24 minutes in his first appearance on Wednesday.
"He knows Wade better than any of us," Pierce said. "He played him every day in practice. I thought he played him great."
Shaquille O'Neal had 17 points and nine rebounds, and Haslem had nine and eight for Miami, which dropped to 1-8 despite scoring 15 straight points in the fourth to tie it. The Heat missed 12 free throws in the game and went 5-for-11 from the line in the fourth quarter.
"D-Wade went for the win. Usually he hits those shots," O'Neal said. "They're a talented team. They've got three Hall of Famers out there and they do very well together. We had a chance to beat them, but we let it slip away."
Rondo worked a give-and-go with Posey with 4:50 left in the third to give Boston its first double-digit lead and energize the crowd. The Celtics led 86-71 with 8:12 left before Miami scored 15 straight points and tied it when O'Neal made 1-of-2 free throws -- getting a third chance because of a lane violation -- with 2:24 to play.
Allen hit a pair of free throws and then Rondo hit a 21-footer to give the Celtics a 90-86 lead. Wade followed his missed 3-pointer with a layup, then Haslem stole Allen's errant pass and fed Daequan Cook for the breakaway and foul.
Cook missed the free throw with a chance to give the Heat the lead, but they finally made it 91-90 when Haslem sank 1-of-2 free throws with 33.5 second left.
Pierce, who sat out much of the third quarter, put back Boston on top.
Pierce said he hurt his back in Wednesday night's game against New Jersey and couldn't do anything on Thursday. He skipped Friday morning's shootaround.
Rivers said he almost kept Pierce out of the game.
"It was close," the coach said. "Up until game time Paul was probably not playing."
But in the end, Rivers gave him the ball.
"Truthfully, I was surprised Coach called the play for me," Pierce said. "I've been struggling all night, but he still has tremendous confidence in me, in all of us, and I wanted to be there for my teammates at the end."
Garnett, Pierce and Allen scored Boston's first 19 points, and the Celtics led 24-18 with two minutes left in the first before Miami scored the last six points of the quarter to tie it.
The new Big Three had 12 consecutive points midway through the second as Boston went on a 9-2 run to take the lead for good. Miami cut it to 52-50 with two quick buckets in the second half, but the Celtics held onto the lead and answered with a 14-3 run that turned a four-point game into a double-digit cushion.
Former Boston University hockey player Travis Roy, who was paralyzed just 11 seconds into his first shift, was honored in the second quarter for his charitable work. ... Smush Parker limped around for a few possessions in the third quarter before heading to the bench with what appeared to be an ankle injury.
LeBron James gets a steal and goes to the other end for the soaring two-handed slam dunk.
Kevin Love launches a full-court pass to LeBron James for the ferocious one-handed dunk, putting the Cavs up 31.
Cleveland busts open Game 5 early as they end the first quarter on a 17-3 run against the Raptors to stretch their lead to 18 points.