Westbrook only scored 12 points on 5-of-16 shooting, but he added 17 assists to tie a career high and grabbed 10 rebounds in the Thunder's third straight win.
Enes Kanter led all players with 27 points and 12 rebounds, and five other Thunder players reached double figures, including Mitch McGary with 14, Anthony Morrow with 12, and Dion Waiters and Steven Adams with 10 apiece.
Miami lost its three-game winning streak and trailed for the final three quarters. The Heat shot just 39.5 percent and were led by Hassan Whiteside's 13 points. Dwyane Wade, Goran Dragic and Mario Chalmers each contributed 12.