Ronald Coleman's 4th quarter fumble was the turning point in Colorado's loss to Arizona State. Deion Sanders took the blame in the post-game.
If you just look at the final score, you might not realize how competitive the Colorado/Arizona State game was. Yes, the Sun Devils ultimately pulled away in the 4th quarter to win by 25 points, but early in the game's final period, the Buffaloes only trailed by four and were approaching the redzone with a chance to take the lead.
That was until Colorado inexplicably inserted Ronald Coleman into the game and put the ball in his hands for the first time in his two-year career in Boulder.