Serge Ibaka scored all 15 of his points in the first half for the Thunder.
The Mavericks, playing without Dirk Nowitzki, Shawn Marion and Vince Carter, were led by Jae Crowder's 21 points and nine rebounds. Brandan Wright added 11 points.
Oklahoma City went on 14-4 run in the first quarter to take a 21-14 lead and was never threatened after that. The spurt was capped by consecutive dunks from Nick Collison and Durant. Collison, a former star at Kansas, drew loud ovations all night.
The Mavericks pulled to 80-71 on a jumper by Bernard James with 5:48 to play, but Dallas was held to only one point over the next four minutes.