The Hawks, coming off a win at Brooklyn on Sunday, began the night fifth in the Eastern Conference.
O.J. Mayo scored 17 points and Chris Kaman had 14 for Dallas. Led by Collison, the Mavericks had three reserves in double figures. Vince Carter had 13 and Brandan Wright 12.
The Mavericks were playing their fourth game in five nights, but they appeared to play with more energy than the Hawks.
"We really had no answer for them," Drew said. "We looked like we were a step slow. ... We didn't guard. We had no defensive presence whatsoever."
The Mavericks' 68 first-half points were also the most allowed by the Hawks this season. Dallas outscored Atlanta 34-25 in the opening period.
"They were by far the more aggressive team tonight," Horford said.
"They really pushed the tempo. I think what killed us was those (15) turnovers. Those were deflating. We're on the break, we're about to score and we throw the ball away. I think that's what really set the tone in the game."
Collison had 18 points in the half as the Mavericks made 29 of 46 shots (63 percent). The Hawks couldn't keep pace despite shooting 56 percent (19 of 35) from the field.
There was a delay after the third quarter when a Hawks cheerleader, identified by the team only by her first name of Kristen, slipped and hit the back of her head and neck during a dance routine. She did not lose consciousness, according to the Hawks, and was taken from the court on a stretcher. She was released Monday night after being examined at the Atlanta Medical Center.
NOTES: The Mavericks' previous high for points in a half was 65 in the second half against the Knicks on Nov. 21. Dallas set its previous scoring high in a 126-99 win over Charlotte on Nov. 3. ... The Hawks' previous high for points allowed came in a 123-104 loss at Houston on Dec. 31. ... Dallas had 33 assists, including five by Nowitzki. ... Kyle Korver, who had 11 points, extended his streak of games with at least one 3-pointer to 60. ... Hawks C Zaza Pachulia (sore right Achilles) missed his ninth straight game.