Oklahoma defeated CMU, 78-73, to advance on Saturday.
Joanna McFarland had a career-high 17 rebounds as part of a double-double to go with 18 points on the day.
The game was tied at 10 when the Sooners rattled off 10 straight points and would not relinquish the lead.
CMU got to within three points of OU early in the second half, but that would be it. Oklahoma led by 11 at 71-60 late and then made free throws down the stretch to secure the victory.
Oklahoma (23-10) will play UCLA on Monday in Columbus, Ohio.