"With him, because he knows everything we run, we were back into running stuff we'd basically put into hibernation while he was out," Boston coach Doc Rivers said. "You just see how comfortable Paul and Ray were."
The NBA's assists leader, Rondo returned after missing seven games with a sprained left ankle. He had four points and eight assists in 34 minutes.
"Obviously I want to be out there with the team, calling the sets," Rondo said. "I'm the most comfortable with it. I know the plays better than Doc."
Glen Davis added 15 points, 11 rebounds and eight assists as Boston won for the 10th time in 11 meetings with Toronto. It was Davis' third double-double of the season.
Davis said Rondo encouraged him to keep shooting after he made just one of seven shots in the first half. Davis made five of seven in the second half.
"No matter what I do out there, no matter if I mess up a play, no matter if I fumble the ball, no matter if I take a bad shot, he is always telling me to keep my head up," Davis said. "That means so much. No matter what you do he is still going to be right there behind you."
Pierce was disappointed with himself after scoring just 12 points and making a season-high six turnovers in Friday's 83-81 loss to New Orleans, but made up for that by hitting 10 of 15 shots, seven of eight free throws and grabbing seven rebounds to help Boston snap a two-game losing streak.
Pierce said Rondo's return was the key to his offensive turnaround.
"Rondo is always the difference when you've got him on the court," Pierce said. "I really couldn't tell he'd been out for seven games. He was a floor general out there, he got guys in the right spots."
Rondo, who came in averaging an NBA-best 13.2 assists, had to be helped off the court in the fourth quarter of a victory over the New York Knicks on Dec. 15, and had not played since.
Rivers didn't expect him to play in this one, either, but changed his mind after a pregame chat with Rondo and trainer Ed Lacerte.
"He was great down the stretch," Rivers said. "You could just see the difference in the execution, all of the passes."
Celtics forward Kevin Garnett, who injured his right calf in Wednesday's loss to Detroit, missed his second straight game.
"I doubt if Kevin plays this week," Rivers said.
Toronto trailed by nine points to start the fourth but cut it 80-75 on a reverse layup by DeRozan and a jumper from Jose Calderon with 5:05 left. The Raptors missed a chance to draw even closer when Dorsey missed two free throws.
Pierce made the Raptors pay by answering with a driving dunk, Allen made a 3-pointer and followed with a jumper in the lane as Boston pushed its lead to 87-75, its biggest of the game at that point.
The short-handed Raptors were without center and leading scorer Andrea Bargnani, who missed his fourth straight game with a sore left calf. Guard Jerryd Bayless, who left Friday's loss at Houston with a sprained left ankle, did not play, and guard Sonny Weems missed his seventh straight game because of back spasms.
DeRozan, who scored a career-high 37 points Friday, had 10 in the opening quarter but Pierce scored 8 as Boston led by one, 24-23, after 12 minutes.
Pierce added 12 more in the second as the Celtics maintained their narrow advantage, taking a 43-42 lead into the half.
DeRozan scored 10 points in the third, including a huge alley-oop from Jose Calderon, but Davis had nine as the Celtics took a 71-62 lead into the final quarter.
Rondo missed three games earlier this season because of a strained left hamstring, sitting out Boston's 102-101 loss at Toronto on Nov. 21. ... Bargnani has missed six of the past eight games with knee, ankle and calf injuries. ... Calderon had 10 assists for the Raptors. ... Toronto outrebounded Boston 49-37. ... The Raptors shot 1 for 14 from 3-point range.