Cousins had 13 points and a career-high 10 rebounds. Cousins hadn't had more than seven rebounds in any game in his career.
“I thought Isaiah was attacking all night,” Sooners coach Lon Kruger said. “I thought he was aggressive and made a lot of good plays. We needed that especially when you go on the road.”
Cousins added four assists.
The Sooners play at West Virginia at 6 p.m. Wednesday in a game televised by ESPNU. The Mountaineers have won three of their last four, including an 81-71 win over Kansas State on Saturday.
West Virginia is the only Big 12 team the Sooners have yet to play this season.
The Sooners swept the Mountaineers last season, winning all three meetings. OU and West Virginia played a nonconference game in the Old Spice Classic before Big 12 play began last year.