Klay Thompson had 34 points and Steph Curry scored 23 for the Warriors, with the pair hitting 14 threes between them.
Curry exchanged shoves with Oklahoma City's Semaj Christon just before halftime, and both were issued technical fouls.
The Golden State star tangled with Christon as the pair vied for position around a jump ball with 5.3 seconds left. Players from both teams converged around them, and there was pushing on both sides. Oklahoma City's Westbrook and Golden State's Draymond Green also got technicals after getting caught in the middle. It was Westbrook's 15th technical of the season.
Curry had the last laugh, hitting a three-pointer to beat the halftime buzzer and running down the tunnel to the locker room.
The game doubled as Golden State's second visit to Oklahoma City since former Thunder star Kevin Durant signed a free agent contract with the Warriors last summer. Durant has been out since February with a left knee injury and is not playing in this one.
The loss drops the Thunder to 40-30 on the season, back into a share of sixth in the Western Conference alongside the Memphis Grizzlies.
- NZ Herald and AP