"After everything we've been through this off-season, we had a lot to prove," Purify said. "This was just the first step in showing everybody what we're about."
It took everything the Buffaloes had to finish it off. Colorado State rallied from an early 17-0 deficit to tie it in the fourth quarter, only to see Colorado take the lead back on Mason Crosby's 55-yard field goal. Colorado went up 27-17 on the next play, when Brian Iwuh snared Justin Holland's off-balance throw and returned it 37 yards for a touchdown.
But the Rams weren't through. Colorado State moved quickly on its next drive, going 80 yards in six plays for John Walker's leaping, 31-yard touchdown catch over Gerett Burl.
The Rams held Colorado to three plays and a punt on its next drive, getting the ball back at their 38-yard line with 2:36 left. Colorado State then reached Colorado's 1-yard line with 30 seconds left and Marcus Houston was stuffed at the line on the next play.
Colorado State coach Sonny Lubick decided to go for the win and screamed at Holland to spike the ball to set up a final play, but the quarterback couldn't hear through the screaming fans. Holland instead called a sweep left to Tristian Walker, who was stopped for a 2-yard loss after being met by Billingsley and Lorenzo Sims.
"It was basically confusion," said Holland, who was 29-for-41 for 403 yards. "We didn't get it blocked right and ran it the wrong way. We didn't have the right personnel in there. It was a terrible way to lose a game."
Billingsley raised his arms and was mobbed by teammates after finishing off Colorado's first win on a defensive stand in 15 years. The fans raced out of the north stands seconds later to the center of the field, joining in a celebration that was still going 15 minutes after the game ended.
The wild reaction seemed fitting considering the Buffaloes had one of the most difficult offseasons any school anywhere could have endured. Former players were accused of rape, coach Gary Barnett's job was in jeopardy and an investigation found recruits were lured to the university with sex and alcohol.
"To see how we circle the wagons and really came together to finish it off, speaks volumes to everybody's character in that locker room," said Colorado's Joel Klatt, who was 13-for-15 for 117 yards.
The pent-up emotion was evident early with the fans and the players. After six years at a neutral site in Denver, the nasty instate rivalry returned to a campus known as the nation's top party school. A Folsom Field-record crowd of 54,954 created a buzz from the start, the fans' screams and chants seeming to echo off the nearby Rockies well before kickoff.
Colorado gave them plenty to cheer about right away, using Klatt's crisp passes and huge holes at the line to march 80 yards in 10 plays on the game's first drive. Purify finished things off, burrowing the final yard for a touchdown.
The Buffaloes didn't take long to get back into the end zone, moving 63 yards in 12 plays on their next drive for Klatt's 1-yard touchdown sneak. The lead went to 17-0 on Crosby's 31-yard field goal late in the second quarter.
The Buffaloes were just as good on defense, swarming and harassing Colorado State from the first snap. The Rams had just 9 yards in the first quarter - to Colorado's 161 - and didn't get a first down until Holland hit John Walker on a 23-yard pass over the middle with 13½ minutes left in the second quarter.
"We fought through that (stuff) for nine months and now we fought through some more," Colorado defensive tackle Matt McChesney said. "There is no quit in this team."
But after surviving Colorado's initial emotions, Colorado State finally got something going, moving 80 yards in 11 plays for a 1-yard touchdown pass from Holland to Matt Bartz on a fourth-down play with 23 seconds left. The Rams kept it going in the third quarter, driving 80 yards for Marcus Houston's 1-yard touchdown on a sweep left that cut Colorado's once commanding lead to three at 17-14.
Colorado missed a chance to extend the lead when Crosby hooked a 42-yard field goal on the Buffaloes' first drive of the third quarter, and Colorado State's Jeff Babcock tied it early in the fourth with a 26-yarder.
"They came back from a deep hole," Lubick said. "They were down 14, down 10 and held together. Even after (Iwuh's) interception, we played hard."