Dirk Nowitzki had 22 points, while Josh Howard and Devin Harris each had 19, as the Mavericks led throughout in a 97-84 victory Saturday that snapped Atlanta's five-game winning streak.
Dallas made its first five shots, including 3-pointers by Howard and Nowitzki, to jump out to a 12-0 lead only 21/2 minutes into the game.
"They hit us on the mouth from the start and we didn't do anything about it," said Hawks guard Joe Johnson, who had 17 points.
"They established themselves defensively as well as offensively. On the defensive end, they beat us up," Atlanta coach Mike Woodson said. "If we're going to be a playoff team, we have to play them the same way they played us."
The Hawks (15-13) missed out on their first six-game winning streak since late in the 1998-99 season, the last time they made the playoffs and finished with a winning record.
Marvin Williams led the Hawks with 18 points.
While the Mavericks had to hold off a late charge by Atlanta, Howard and Nowitzki kept it from getting too close.
Nowitzki ended a wild sequence in which both teams missed layups by making a baseline jumper to put the Mavs up 89-79 with 3:07 remaining.
Former Hawk Jason Terry had 14 points for the Mavericks.
NEXT: at Cleveland
WHEN: 7 p.m. Wednesday
TV: Fox Sports Net South
DON'T MESS WITH TEXAS
Atlanta will finish with a 9-4 December after Saturday's loss to Dallas.
It was no surprise that the Hawks' five-game winning streak ended in Dallas. The Hawks have lost four games in a row in Dallas and nine of the last 10 in the Lone Star state.
The Hawks were within six with 4:53 left after Marvin Williams converted a three-point play and then got credited with a basket on a goaltending call against Dampier. Atlanta never got closer after that.