Backup quarterback Trevor Knight, who replaced starter Blake Bell due to injury in the second quarter, added 123 rushing yards for Oklahoma (8-2, 5-2 Big 12). The Sooners, who had four touchdowns of more than 50 yards, finished with 405 rushing yards - the most under coach Bob Stoops.

Grant Rohach went 21-of-34 for 179 yards and two interceptions in his second start for Iowa State (1-9, 0-7). Quenton Bundrage had six catches for 66 yards for the Cyclones, who have lost seven straight.

Iowa State outplayed the Sooners in the first half, taking an early lead on backup quarterback Sam Richardson's 4-yard option keeper. The teams traded field goals, but Oklahoma stole momentum when Jalen Saunders slipped a couple of tacklers on a 91-yard punt return touchdown to tie the game at 10 with 1:09 left in the first half.

The Sooners offensive line opened huge holes for Williams (69-yard score) and Brennan Clay (63-yard TD) on their third-quarter touchdowns and Knight started the fourth quarter with a 56-yard score on an option keeper. Williams added another 19-yard touchdown run and Oklahoma backup Kendal Thompson hit Aaron Ripkowski for a 3-yard TD to cap the scoring.

GAME NOTEBOOK: Stoops (157-39 since 1999) tied Barry Switzer (157-29-4 from 1973-88) for Oklahoma's most coaching victories. ... The Sooners had two 100-yard rushers for the first time since the 2008 Big 12 Championship game against Missouri. ... The Sooners recorded their 11th perfect home record under Stoops.