Russell Westbrook added 18 points, nine assists and eight rebounds for the Thunder, who led most of the game but had to fend off a late Portland charge to improve to an NBA-best 29-8.
The Trail Blazers had two chances to take a late lead, but Nicolas Batum missed a layup with 9 seconds left and LaMarcus Aldridge misfired on a 19-foot jump with 1.2 seconds remaining.
Aldridge finished with a season-high 33 points with 11 rebounds and Batum contributed 21 and seven for the Blazers, who lost a second straight following a four-game winning streak.
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