39-31 over No. 6 Oregon sent Oklahoma State fans onto Boone Pickens Stadium field, where they tore down a goalpost and carried it about 15 minutes to Theta Pond.
23 1/2-point underdog Oklahoma State secured Eric Morris' first win and snapped a 21-game skid against FBS opponents with a late fourth-down stop.
Drew Mestemaker drove the upset with 317 passing yards, two touchdown throws and 109 rushing yards, plus a leaping rushing score after a shaky debut against Tulsa.
Big 12 rules could bring a $50,000 fine for the field storming, though the league rescinded Colorado's 2025 penalty after issuing one to Arizona State and Colorado.