BYU's run defense only allowed 114 rushfor the game, and 13 of those yards came on Arizona's last series (after the pick 6). Arizona had been averaging 146 yares per game on the ground.
Also the defense held them to 276 yards passing, which was slightly below their average. Considering the fact that they could not move the ball on the gorund to keep them below their average and well below 300 yards of passing says plenty about how dominant the defense was.