Westbrook wrapped up his eighth career triple-double on a rebound with 4:55 left in the third quarter. He left the game moments later and did not return. He finished with 13 points, 10 rebounds and 14 assists.
Serge Ibaka and Reggie Jackson each scored 14 points and Perry Jones added 12 for the Thunder, who shot 57 percent from the field in their most lopsided victory of the season.
James Anderson scored 20 for the 76ers, who lost their 15th in a row, their longest slide since a 15-game skid in 1994. Philadelphia shot just 34 percent.
Durant, who made 14 of 20 shots from the floor, did not play in the fourth quarter.
Caron Butler, the Thunder's recent acquisition, entered for the first time as a member of the team with 5:26 left in the first quarter and received a loud standing ovation. He made his first basket, a jumper, with 2:18 left in the opening period.
Westbrook had eight assists in the first 6:34 to help the Thunder take a 24-15 lead. He got his 10th assist on a long bounce pass to Durant with 4:55 left in the second quarter. Westbrook finished the first half with 11 assists, a Thunder record for a half. He didn't score until he made a layup with 1:50 left in the first half. His second basket was a 29-foot 3-pointer.
Durant scored 21 points in the first half on 8-for-11 shooting to help the Thunder take a 61-45 lead at the break.
The 76ers made 3-pointers on three consecutive trips down the floor - the first two by Byron Mullins and the third by Anderson - to cut what had been a 22-point deficit to 15 midway through the third quarter.
The Thunder bounced back and led 98-76 at the end of the period. Durant scored 21 of Oklahoma City's 37 points in the quarter.
The crowd cheered loudly when Oklahoma City's 7-foot-3 center, Hasheem Thabeet, stepped out of his usual element and drained a 17-foot jumper that put the Thunder up 110-79 with 7:33 to go.
NOTES: Jones and C Steven Adams started for the Thunder in place of injured G Thabo Sefolosha and C Kendrick Perkins. ... The 76ers have allowed at least 100 points in 14 of the 15 losses during their skid. All but three of the defeats have been by double digits. ... Thunder G Jeremy Lamb made a layup at the first-quarter buzzer after catching a pass from Durant that traveled most of the length of the court. ... The Thunder shot 70 percent in the first quarter to take a 37-23 lead. ... 76ers coach Brett Brown was issued a technical foul with 5:30 left in the second quarter.