Phil Forte scored all 13 of his points in the second half to lead Oklahoma State to an 82-75 victory over No. 7 West Virginia on Saturday.
The Cowboys (15-8, 4-6 Big 12) have the league's longest current winning streak at five after No. 2 Baylor and No. 3 Kansas both lost on Saturday.
West Virginia (18-5, 6-4) had a chance to move into a second-place tie with Baylor but couldn't match Forte's production down the stretch.
Forte scored nine points over the final 5 minutes.
Jeffrey Carroll led the Cowboys with 20 points but he had only three after halftime and Jawun Evans added 18.
Evans' driving layup put Oklahoma State ahead to stay, 71-69, with 4:17 left, and Lindy Waters' 3-pointer and four free throws by Evans put the Cowboys up 78-74.
Forte sealed the win by making all four of his free throw attempts in the final minute.
Redshirt freshman Lamont West scored a season-high 21 points for West Virginia and Tarik Phillip added 15.