STILLWATER, OK - OCTOBER 29: Tight end Zac Veatch #86 of the Oklahoma State Cowboys hurdles safety Kyzir White #8 of the West Virginia Mountaineers during the first half of a NCAA football game at Boone Pickens Stadium October 29, 2016 in Stillwater, Oklahoma. (Photo by J Pat Carter/Getty Images)

One of college football's undefeateds has officially fallen

A huge blow for the Big 12?

Another one bites the dust!

West Virginia got a big win at home over TCU last week, but the real question was if they could copy that kind of performance against a good team on the road.

They couldn't.

Oklahoma State upset the Mountaineers on Saturday, walking away with a 37-20 win in Stillwater. The Cowboys defense was excellent, but where they won the game was a steady performance from quarterback Mason Rudolph. Up seven at the time, Rudolph engineered a fantastic drive to lead Oklahoma State to a score with five minutes left in the fourth quarter. The score gave Oklahoma State a 14-point lead, which proved to be insurmountable.

Oklahoma State moves to 6-2 on the season, which is a good way to rebound after a shocking loss to Central Michigan on a fluke play earlier in the season. West Virginia, meanwhile, falls to 6-1, and the Big 12's hopes at making the College Football Playoff likely all lay on Baylor right now.