Courtney Williams scored 16 points and Laura Ferreira had 12 of her 14 in the second half and No. 20 South Florida handed Oklahoma State its first loss 68-46 on Sunday.
The Bulls (7-2) led 31-21 at the half despite going 2 of 13 from 3-point range and shooting 40 percent. They pulled away in the second half by making 5 of 8 behind the arc and 14 of 28 overall.
Oklahoma State (8-1) never got untracked, shooting just 33 percent in the first half and finishing at 30 percent (18 of 61), including 1 of 12 from 3-point range.
Brittney Martin led the Cowgirls with 19 points but her streak of 20-point games ended. Kaylee Jensen added 15.
OSU won the battle of the boards 40-39 but it was the first time it hadn't bested an opponent by double figures.
South Florida is 7-0 at home, having only lost at ranked Baylor and St. John's.