DALLAS -- Antoine Walker scored 10 of his 29 points during a third-quarter surge, and Boston gained ground in the Eastern Conference playoff race with a 104-99 victory over the Mavericks on Saturday night.
Eric Williams added 18 points off the bench and Paul Pierce scored 15 for the Celtics, who moved within a game of Milwaukee and Orlando, tied for the eighth and final Eastern Conference playoff spot.
Boston won its third straight and its seventh in the last eight.
Michael Finley's 28 points, rookie Greg Buckner's career-high 25 points and Dirk Nowitzki's 21 points and 11 rebounds paced the Mavericks, who had their three-game winning streak snapped.
The Celtics led by as many as 11 in the fourth quarter before the Mavericks made a late charge, using a 12-3 run capped by Buckner's 3-pointer with 9.8 seconds left to reduce the deficit to 101-99.
But Pierce converted two free throws with 8.3 seconds left for a 103-99 advantage, then Buckner missed a layup with four seconds remaining.
Boston opened the third quarter with a 14-4 run capped by Walker's layup for a 63-51 lead. Walker's 3-pointer with 4:03 left in the quarter expanded the Celtics' advantage to 76-62.
The Celtics were in front 80-72 entering the fourth quarter, but the Mavericks cut the deficit to 82-79 on Finley's 3-pointer with 10:21 left.
Boston then went on an 8-2 run capped by consecutive baskets from Walker for a 90-81 edge with 7:36 remaining.
Notes: Mavericks owner-to-be Mark Cuban said he has no interest in signing guard Isaiah Rider, who was waived by Atlanta on Friday. Cuban recently released controversial forward Dennis Rodman following a 12-game tryout, and Cuban said, "I learned that lesson.". ... Cuban is shopping for a team plane and has made a bid of $43 million on a 757 currently owned by the republic of Argentina. ... Buckner got his first start as Dallas opened with four guards and Nowitzki. The Mavs used their 26th different starting lineup this season.