Thunder 120, Rockets 91: Kevin Durant scored 24 points and Russell Westbrook had 19 points, 10 assists and eight rebounds as host Oklahoma City routed Houston in the opener of the first-round Western Conference series.

Serge Ibaka added 17 points and seven rebounds for the top-seeded Thunder, who never trailed en route to matching the largest margin of victory in a postseason game in the franchise’s five seasons since relocating from Seattle. Game 2 is Wednesday in Oklahoma City.

James Harden scored 20 points as the only starter in double figures for the eighth-seeded Rockets, who were playing their first playoff game in four years. The other Houston starters combined for 28 points.

The Thunder led by 13 points at halftime and quickly increased the advantage to 74-54 on two free throws by Westbrook with 8:07 left in the third quarter. The lead was 23 entering the final quarter and Oklahoma City’s edge reached 102-69 on Derek Fisher’s 3-pointer with 9:18 remaining before the Thunder cruised to the finish.

Oklahoma City jumped out to a 13-2 lead as Houston took six minutes, 14 seconds to make its first field goal. The Rockets battled back to tie the score at 38 midway through the second quarter but a 14-1 surge helped the Thunder take a 60-47 lead at the break.

GAME NOTEBOOK: The Thunder had a 9-1 edge in blocked shots. … The Rockets shot just 36.3 percent from the field and were 8-of-36 from 3-point range. … Fisher made three of Oklahoma City’s 10 3-pointers.