With Heisman hopeful Will Grier coming to town and Sam Ehlinger playing lights-out football as of late, it was a game that was destined to be a shootout. In the end, it came down to Grier making the winning play, ripping the Big 12 Championship hopes away from Texas. Here are three reasons why the Mountaineers pulled out the win at Darrell K. Royal-Memorial Stadium.

Banged-up defense

Safety Brandon Jones, one of the biggest playmakers on the defense, went on the injury report late this week after suffering an ankle injury in practice. The Longhorns missed him dearly, as Will Grier threw for 346 yards and 3 touchdowns on the day. They also missed his presence in the run game (more on that later).

Both starting cornerback Devante Davis and defensive end Breckyn Hager were sidelined with injuries in the first quarter. Neither returned to the game, and the lack of experience on the Longhorn defense was on full display.

True freshman corner Anthony Cook is a week removed from the first start of his career, where Oklahoma State bullied him in the first quarter. Grier went after him on the perimeter, and Cook struggled to keep up. And without Hager, the pass rush was nonexistent. Texas did not have a single sack on the day.

Running wild

The Texas defense prided itself up to this point on stopping the run. Against USC in Week 3, the Longhorns held that offense to negative yards on the ground. Yet they had no answer for the Mountaineer rushing attack. The holes were gaping for West Virginia in the run game. They consistently picked up big yardage plays with zone blocking schemes on first and second down.

To give credit where credit is due, the offensive line for the Mountaineers played outstanding. West Virginia averaged 7 yards per carry, and got a push off the line of scrimmage on nearly every running play.

The injury to Hager did not help, but the Longhorns simply could not fill gaps in the running game. And when the speedy West Virginia backs made it to the second level, the tackling from the Texas secondary was as poor as it has been all season long.

Mental mistakes abound

This Texas team has been good enough to beat nearly every team they’ve played. Yet in the last two weeks, they cannot keep from beating themselves.

Early on, it was extending West Virginia drives with penalties and defensive miscues. Grier capitalized on a blown coverage for a 60-yard touchdown pass, then on a horsecollar on third down that kept a drive going that would later result in a touchdown pass.

Midway through the second quarter, a missed tackle in the secondary led to a 55-yard touchdown run.

The killer for Texas came on a 33-yard touchdown pass with 16 seconds remaining. Somehow, safety Caden Sterns allowed a receiver to slip behind him, and Grier made him pay, tossing a perfect pass to pull within one. The following two-point conversion won the game for the Mountaineers.