Westlake improved to 2-4 overall and 1-1 in the region, while Hillcrest dropped to 2-4 and 0-2. The Huskies have been outscored 78-14 in their Region 7 losses.
The Thunder overcame the shock of losing senior running back Daniel Nugent on their fourth play of the game.
Nugent was injured after losing 3 yards on a sweep. He remained on the field for 20 minutes while being treated for a leg injury. He then was transported to the hospital in an ambulance.
When play resumed, Westlake completed a 13-play, 92-yard drive and grabbed a 6-0 lead on Williams' 13-yard touchdown pass to a wide-open Tyler Diaz.
After a Hillcrest fumble, the Thunder quickly made it 12-0 when Rentfro took a handoff from Williams and threw a 23-yard touchdown pass to Austin Fotheringham.
The Huskies stayed close by driving 65 yards in nine plays on their next possession. Sophomore quarterback Tanner Thompson scored on first-and-goal from the 1 with 1:08 left in the first quarter.
When Curtis Willits converted the extra point, Hillcrest trailed 12-7.
The Thunder nursed their narrow lead into the third quarter, when Westlake used a roughing the passer penalty and a 24-yard pass from Williams to River Sanderson to reach the Hillcrest 5.
Jed Murri powered up the middle for a touchdown on a first-down play to bump the lead to 19-7 with 6:15 left in the third quarter.
Willets' 34-yard field goal made it 22-7 with 10:31 remaining, and Westlake rode its defense the rest of the way.