Rose Hammond sparked the Sooners with a career-high 12 points as No. 4 seed Oklahoma escaped No. 13 seed Illinois State 69-61 at Mackey Arena in West Lafayette, Ind.
Oklahoma (22-8) advances to play the SMU-Notre Dame winner on Tuesday for the right to advance to the Sweet 16.
Illinois State used a 7-0 run late in the first half to take a 29-27 lead on the Sooners, but Hammond quickly tied the game with a bucket. Amanda Thompson gave Oklahoma a two-point halftime lead with a 17-footer just before the buzzer.
Oklahoma then managed to outscore ISU 38-32 in the second half despite shooting 8.3 percent (1-for-12) from 3-point range.
Ashely Paris led the Sooners with 13 points. She added five rebounds. Twin sister Courtney Paris racked up another double-double with 12 points and 13 boards.
Danielle Robinson also scored 12 points.
The win snapped a three-game losing skid by Oklahoma.