"We're nowhere near a perfect team," Pierce said. "We're still trying to build, trying to get better.
"Definitely, it's one of our better games."
Rasheed Wallace and Eddie House scored 15 apiece. Kevin Garnett added 12 points and 10 rebounds, and Pierce scored 14 even though he sustained a stinger on his right shoulder and hit just 4 of 12 shots.
Boston scored 10 straight late in the third quarter, making it a 20-point game and sending the Bulls to their 10th loss in 12 games.
Derrick Rose scored 19 for Chicago. Luol Deng added 17 but missed 4 of 6 free throws late in the third quarter, and the Bulls capped a particularly brutal seven-day stretch with another blowout loss. They were routed by Toronto and Atlanta and fell to New Jersey in between, and after an overtime win over Golden State on Friday, they watched Boston run away with this one in the second half.
Chicago went the final 6:18 of the third quarter without a field goal and shot 32.6 percent overall. With a 71-61 lead, Pierce hit two free throws to start a 10-0 run that Garnett capped with an alley-oop layup from Rondo with 1:26 left in the quarter.
"We just didn't have anyone step up at that time," Rose said.
The Bulls hardly resemble the team that pushed Boston to seven games before losing a thrilling first-round playoff series last season, albeit with Garnett sidelined by an injured right knee. Rose and Joakim Noah have questioned the team's effort and the pressure on coach Vinny Del Negro is mounting.
"We just have to keep playing hard," Deng said. "I don't know what else to tell you."
The Celtics, who blew out the Bulls in October, look more like the team that won the championship than the one that struggled to get by Chicago last season, settling in after a volatile start.
Things got testy about 3½ minutes into the game when Brad Miller basically clotheslined a driving Rondo, who gave him a bloody mouth in the playoffs. That delighted the crowd, even if it resulted in a flagrant foul.
Rondo said he expected some retribution from Miller, considering his hard foul late in Game 5 of the playoffs left him with a bloody mouth.
"I think he tried to go for my face, but he hit me in my nose a bit as well," Rondo said.
Miller said "it's not really payback, but everybody knows what happened." He said it was more about a center refusing to let a guard go in for a layup, adding, "You've got to win that battle."
While Pierce said Miller's not a dirty player, Ray Allen "thought it was excessive."
Rondo, meanwhile, said the blow "didn't hurt" and he's "been hit way harder."
"I'm not going to get intimidated by it," he said. "The next time we play, I'm going to drive whether it's him, whether it's Noah or anybody. It can be Shaq, I'm still going to drive. That's what I do."
- Boston has not lost since falling 83-78 to Orlando on Nov. 20.
- The Celtics went from losing a club-record 18 in a row in 2006-07 to winning the championship next year, so it's no surprise that coach Doc Rivers endorsed Del Negro. "Listen, I believe this will work out for him," Rivers said. "I know what he can do. I coached against him last year in the playoffs, and I just hope he gets a chance to do it." For Rivers, it helped that the Celtics landed Garnett and Allen before their championship season. The Bulls have been hit by injuries and lackadaisical play overall.
- Rondo was having a little fun at his coach's expense after Kentucky, his school, beat Indiana on Saturday. Rivers' son Jeremiah plays for the Hoosiers. "I can't even tell you how hard Rondo's been the last three hours," Doc Rivers said. "That's all right. I control the minutes."
- The Bulls go from hosting the Eastern Conference leader to the Western Conference leader when the Los Angeles Lakers visit on Tuesday.