San Antonio rallied behind its reserves and went up 41-39 on Tiago Splitter's basket underneath before the Thunder pushed ahead for good with a 12-2 response.
Oklahoma City stretched its lead with 11 straight points during the third quarter, punctuated by Nick Collison's putback that made it 71-56 with 4:27 remaining in the period.
The Spurs tried going to their cornerstones to break up the spurt but Duncan had the ball stolen by Westbrook and then a shot blocked by Ibaka on consecutive possessions and Parker followed by missing a corner 3-pointer off the side of the backboard and then getting a fast-break layup swatted by Durant.
Collison then scored off of Sefolosha's missed 3-pointer, and it was on the next possession that Ibaka flexed his muscles after grabbing three straight offensive rebounds.
"He's growing every single day," Durant said. "He's shooting the jumper well, he's taking guys off the dribble. Of course, you know he blocks shots and rebounds but his offensive game is expanding and that's what we need."
NOTES: After playing 16 of their first 24 games at home, Oklahoma City plays 15 of its next 21 games on the road. The roughest stretch is another three weeks away, when the Thunder play 11 of 13 games away. ... Referee Bennett Salvatore called a technical foul from across the court against Spurs coach Gregg Popovich as he complained to official Scott Twardowski after calling a timeout during Oklahoma City's 11-0 third-quarter run. ... Oklahoma City's last 11-game win streak was in 1996 as the Seattle SuperSonics.