WACO, Texas (AP) - Aaron Karas threw three touchdown passes and the Baylor defense provided a fumble return for a score and a goal-line stop that prevented a go-ahead touchdown early in the fourth quarter, helping the Bears stun Colorado 42-30 Saturday.
Rashad Armstrong ran for 166 yards and two touchdowns, including a 55-yarder that sealed one of the most surprising upsets in the eight-year history of the Big 12.
Baylor (3-2, 1-0) has won three straight for the first time since going 3-0 in 1996, which came before its first Big 12 game ever. The Bears were an ugly 4-52 in conference games, having lost seven straight and 37 of 38. The Buffaloes (2-3, 0-1) are on their first three-game skid since opening 0-4 in 2000.
And they didn't beat lowly Kansas or Iowa State as they did in three of their previous victories. This was two-time reigning North champion Colorado, which was ranked No. 17 a few weeks ago.
It didn't start out memorably as Baylor was shut out in the first quarter, making it nine straight quarters against Colorado without a point.
Then came a span fans won't soon forget: a spurt of 35 points in 17:15.
Karas led the Bears to touchdowns on four of five possessions, with the only non-score coming on a drive that began with 59 seconds and no timeouts at the end of the first half. Then the defense put Baylor ahead for good and kept it there.
Derrick Cash sacked Erik Greenberg, forcing a fumble that Jamaal Harper returned 7 yards for a touchdown that put the Bears up 28-23. Two snaps later, Greenberg fumbled a snap and Justin Crooks recovered, leading to a 3-yard touchdown by Armstrong and a 35-23 advantage.
Colorado got within 35-30 when a botched punt by Baylor set up a 29-yard touchdown pass from Greenberg to Derek McCoy. With 1:11 left in the fourth, it seemed like the Buffs' pedigree might help it pull through _ or that Baylor would be haunted by its losing ways.
Instead, on the first play of the fourth quarter, Crooks helped throw Brian Calhoun for a 2-yard loss on fourth down from the 1. The Bears then drove all 97 yards, with Armstrong doing most of the damage, especially his long TD run that made it 42-30.
The Buffs turned to Joel Klatt, who was superb in winning the first two games but hadn't played since hurting his throwing shoulder in the third game. His first pass was intercepted, marking the first of his career on his 93rd pass.
Baylor scored its second-most points in a Big 12 game and most in regulation. This was only the fourth time the Bears led a conference game after three quarters, and first since a 1998 loss to Texas.
Karas was 18-of-28 for 207 yards, with TDs of 8, 25 and 26 yards. Robert Quiroga had the 25-yarder among his eight catches for 113 yards.
Greenberg was 16-of-29 for 346 yards with two touchdowns, and Klatt finished 3-of-8 for 53 yards.