BOSTON -- Kevin Garnett offered polite praise of the Miami Heat before Paul Pierce interrupted the postgame news conference and said, "Man, I am going to tell you the truth."
Then he did.
"They got D-Leaguers our there, so I think we just handled our business," the Boston forward said, listing some of the five Miami players who spent time in the developmental league this season. "We're supposed to do that. We knew this was a game we were supposed to win, and we just focused from the jump and went out and did it."
Then he slapped Garnett on the head and said, "Let's go."
The Celtics limited Miami to 17 baskets -- the fewest in the NBA's shot-clock era -- and coasted to an 88-62 victory on Sunday night to solidify their hold on the league's best record and leave the Heat firmly in control of the worst.
Garnett scored twice before Miami made a basket, Ray Allen followed with a pair of 3-pointers and Boston opened a 27-4 lead in the first quarter. Celtics coach Doc Rivers started subbing for his starters just 7:10 into the game, letting the backups handle the end of the first quarter, most of the second and all of the fourth.
"We are trying to prepare and get ourselves ready for the playoffs," said Garnett, who finished with 12 points, five assists and eight rebounds. "The competition is what should motivate you. We definitely didn't want to lose the game, or mess around. So we just came out aggressive and never looked back."
Leon Powe had 17 points and 13 rebounds and a team-high 27 minutes for Boston. James Posey, the 10th man in, spent more time on the court (21:33) than Garnett (21:30).
The Boston bench built a 31-point lead before Miami made its last two shots to finish with 17 field goals, still fewer than the 18 made by the Chicago Bulls against the Heat on April 10, 1999.
"Oh, did we?" said Ron Rothstein, the Miami assistant who ran the bench while head coach Pat Riley missed his fourth game to resume his college scouting tour. "How about that?"
Ricky Davis had 14 points and six rebounds and Chris Quinn had scored 14 with eight assists for the Heat (13-60), who lost their third straight and sixth out of seven.
"We tried to do a lot of stuff," Rothstein said. "There's just not a lot of stuff we can run with the new guys, and they just took out everything we tried to run. It's tough."
The Celtics, who are 58-15 with nine games in the regular season, already have their highest win total since 1986-87, when Larry Bird led the defending NBA champions back to the finals. The year before, Boston won 67 games and the last of its 16 titles.
The Celtics scored 11 of the game's first 13 points, then took a 23-point lead as Miami made just one of its first 15 shots. Davis made a three-point play and Blake Ahearn followed with a 3-pointer to help the Heat avoid their worst quarter of the season.
Miami shot 17.6 percent in the first quarter and 28.8 percent for the game.
Davis needs four points to reach 1,000 for the sixth consecutive season. ... Rivers and Riley sat together for last week's Georgetown-Davidson NCAA tournament game. Rivers was watching his son, Jeremiah; Riley was scouting. ... Boston outrebounded the Heat 54-31 and outscored them 34-4 on second-chance points. The edge on points in the paint was 38-10, Boston.