Kamari Murphy scored 12 points and Marcus Smart and Markel Brown scored 11 points each for the Cowboys (10-1), who reeled off a fifth straight victory.
Oklahoma State got hot from beyond the arc to start the game, establishing a quick 14-4 lead, and never looked back after that.
Jud Dillard led the Golden Eagles (6-6) with 18 points and six rebounds.
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