It was the Western Conference-leading Thunder's sixth straight victory.
Jeremy Lamb came off the bench to score 19 points, and former Celtics center Kendrick Perkins had nine rebounds for Oklahoma City. The Thunder were playing with neither Durant nor Westbrook for the first time since the franchise moved from Seattle in 2008.
Jeff Green scored 16 points and Gerald Wallace scored 12 of his 13 points in the first half, before the Thunder pulled away with a 17-2 run in the third quarter. Rajon Rondo had eight assists and five points in his fifth game since returning from reconstructive knee surgery.
The Celtics have lost 13 of 15 games.
Durant had been scoring in bunches this month, with nine straight games of at least 30 points. But coach Scott Brooks announced before the game that he would sit to rest his ailing right shoulder; Brooks said he did not know how long his star forward would be out.
"It's the best thing for him," Brooks said before the game. "Until he's ready to play, he's not going to play. Regardless of how he feels and what he wants to do."
The Thunder allowed the Celtics to open a five-point lead early in the second quarter but then scored 18 of the next 22 points to take a nine-point lead.
It was a two-point game after Boston scored the first basket of the second half, but Oklahoma City opened a 60-53 lead and then scored 17 of the next 19 points.
In all, Oklahoma City outscored the Celtics 27-13 in the third.
Notes: Rondo became the sixth player in Celtics history to reach the 4,000-assist plateau. Bill Russell is next, with 4,100. ... The Thunder have the best record in Western Conference and are 6-0 on the road against Eastern Conference teams. They will try to remain perfect Saturday at Philadelphia... Celtics F Jared Sullinger dislocated his right index finger in the first half but returned to the game.