Jason Terry scored 29 points and Josh Howard added 19 points and 11 rebounds to lead Dallas to a 109-95 victory on Friday night.
Dirk Nowitzki scored 20 points and Devin Harris added 18 for the Mavericks, who have the NBA's best record at 57-11.
It was the fifth win in a row for Dallas after losing two straight for the first time since starting the season 0-4. The Mavericks snapped that skid with a 106-101 home victory over the Celtics on March 16, but had to claw back from a 10-point halftime deficit to do so.
"That was the first one we won, so it got us started," Terry said. "More importantly than a winning streak, we're just trying to get back to playing Maverick basketball on both ends of the floor. I think we're headed in the right direction."
This time, Dallas led by as much as 23 and never trailed to improve to 4-0 -- including impressive wins over Detroit and Cleveland -- on its six-game road trip.
The Mavericks held the Celtics to 36 percent shooting, including 22 percent in the third quarter when they outscored Boston 34-20 to turn a 56-51 halftime lead into a blowout.
"Two weeks ago we had a little slippage going on, made some mistakes defensively," Nowitzki said. "But I think we've cleaned them up. Defensively, I think we've looked pretty sharp the last couple of games. Hopefully, we can keep that up going into the playoffs."
Paul Pierce led Boston with 30 points, but was held to 5-of-18 shooting. Al Jefferson, who entered the game averaging 19.8 points since the All-Star break, was held to four.
After the Celtics scored 15 straight points in the second to erase most of what had been a 21-point deficit, Dallas opened the third on a 10-2 run to blow it open.
Terry opened the second half with a jumper, and Nowitzki followed with a 3-pointer to extend the lead to 61-51. Following a jumper by Pierce, Nowitzki made two free throws and Howard nailed a 3 to give Dallas a 66-53 lead.
"Dallas has such a good team, they have the ability to turn it on when they want to," Pierce said. "It just seemed like they took their game to another level."
The Celtics never got to within 10 from there. Boston lost its third straight, dropping to an Eastern Conference-worst 20-49.
Only Memphis has a worse record in the NBA.
Gerald Green scored 19 for Boston, and Jefferson had 11 rebounds but was 1-of-11 shooting. With Jefferson struggling, Dallas was able to outscore Boston 54-18 in the paint.
"They had a game plan for us from the jump," Jefferson said. "They trapped me every time I got the ball, and made Paul try to beat them by himself. And Paul didn't have the backbone of us to help him."
With Dallas comfortably ahead 98-75 midway through the fourth, Mavericks coach Avery Johnson inserted Jose Juan Barea, a rookie out of nearby Northeastern.
Barea, who went undrafted but signed with Dallas as a free agent last summer, scored five points in seven minutes while a large contingent of Northeastern fans chanted his name.
"I was hoping at some point -- even if it was just for a second -- we could get him in tonight," Johnson said. "I thought about it in the first half, but it was a little too early."
At first it looked as if Dallas' lead would be substantial enough to put Barea in before halftime.
Howard scored five quick points to help the Mavericks open the game on a 10-2 run while holding Boston without a field goal for more than four minutes.
Pierce snapped that stretch when his jumper cut the deficit to 10-4 with 7:53 remaining in the first. But Dallas scored the next eight points and extended its lead to 33-16 by the end of the first.
Boston then outscored Dallas 35-23 in the second. Still, the Mavericks won their seventh straight and 13th of 14 against Boston.
Boston F Brian Scalabrine sat out with a strained left hamstring he injured in Wednesday's 92-84 loss to Charlotte. ... Boston missed its first eight shots. ... Dallas C DeSagana Diop blocked three shots in four minutes in the first quarter. He finished with five blocks and 11 rebounds. ... Dallas scored 26 fast-break points, compared to Boston's 12.