Garnett played 18 minutes, hitting all five field-goal attempts while scoring 12 points. He added two rebounds and two assists in his third game back since missing 13 with a sprained right knee. He left a few minutes after scoring on an alley-oop pass from Rajon Rondo -- a similar play on which he hurt his knee against Utah on Feb 19 -- but was fine.
Boston trailed 55-52 midway into the third quarter before scoring 14 straight points to take control. The Celtics took the lead for good at 56-55 on Garnett's short jumper in the lane before his alley-oop brought the relatively quiet crowd to its feet.
"The reason I was laughing is because it was such a long time since I had one from so far out, but it felt good," Garnett said. "I'm trying to give Paul [Pierce] and Ray all I have so far until I get back."
After Garnett's dunk, Allen scored on a breakaway layup before he nailed a 3-pointer from the left corner 36 seconds before Pierce's 3 from the top, closing the spree.
"We have such a great chemistry when our starting five is out there," Pierce said. "We don't like him on the bench. We like him on the floor."
Rondo added 14 points and seven assists, while Kendrick Perkins scored 12 points and had 13 rebounds for Boston (54-18). The Celtics have a one-game lead over Orlando for second place in the Eastern Conference. The teams meet in Florida on Wednesday night.
But it was Garnett's alley-oop dunk midway into the third quarter that had to make his teammates feel great.
"He has that presence," Boston reserve forward Mikki Moore said.
Added Stephon Marbury, a teammate of Garnett's in Minnesota: "He just changes the complexity of the game."
Zach Randolph led the Clippers with 17 points and 14 rebounds, while Baron Davis had 13 points, eight assists and seven boards.
"He didn't really get a lot of minutes tonight, but the guys coming off the bench seemed to be playing inspired basketball," Los Angeles center Marcus Camby said about Garnett's time on the floor.
Boston led 70-60 after three and pushed it to 83-65 when Glen Davis broke out on a fast break, dribbled behind his back before hitting Eddie House, who nailed a 3-pointer from the left corner with 7:01 to play.
"If you don't get numbers [on the defensive end] Ray Allen's going to knock down shots on you, Eddie House is going to make shots on you, and it's going to be difficult," Clippers coach Mike Dunleavy said.
The Celtics led 31-18 after one quarter, but soft defense and poor shooting by their bench allowed the Clippers to climb right back. Boston's reserves shot 2-for-12 in the opening half.
Boston coach Doc Rivers said before the game that he was going to "back up" Garnett's minutes "a bit" for the next few games even though the team faces Orlando on Wednesday. "If we can't get the top seed, we want to be healthy," he said. ... Allen passed Walter Davis for 36th on the NBA's career scoring list. ... The Clippers have just five wins against teams over .500 this season, with their last against the Celtics at the Staples Center, 93-91 on Feb. 25. ... Boston had just four field goals in the second quarter.