Boulder, Colo. ? Grant Stucker’s patience finally paid off.

The fifth-year senior quarterback made his first start Sunday night and led Colorado State to a 23-17 upset of Colorado, the Rams’ first victory in Boulder since 1986.

Stucker barely beat out Jon Eastman last week for the starting job, a year after losing out to Billy Farris.

“One thing you’ve got to look at it, 50 years down the road, do you think you could’ve stuck it out, regardless if you get the start or not? It’s something I didn’t want to have — regret,” Stucker said.

“I’m very happy that I was able to have that patience to stick it out.”

So are the Rams and their fans, who stormed the field to celebrate the second upset for the Mountain West Conference over a Big 12 team in 24 hours, coming on the heels of BYU’s stunning 14-13 victory over third-ranked Oklahoma.

Stucker threw a 13-yard touchdown pass in the first quarter to new running back John Mosure, who also had a 1-yard TD run as the Rams (1-0) took the Folsom Field crowd out early by jumping out to a 17-0 lead.

That helped calm down Stucker, whom Rams coach Steve Fairchild said had a poor week of practice.

“I wasn’t sandbagging anybody. First-year quarterback, there’s just some growing pains,” Fairchild said. “We’re not out of the woods yet with him. I think he’s a talented young man. Hopefully he’ll keep getting better. … I’ll certainly pat him on the back and give him his due. That’s not easy, coming into this place and trying to win a game like that.”

Colorado coach Dan Hawkins — who’s entering a do-or-die fourth season at Boulder — kept his starter a secret until just before kickoff when his son, junior Cody Hawkins, got the nod over Tyler Hansen.

That decision was met with derision by the Buffaloes’ student section as Colorado’s offense struggled behind Hawkins, who completed 7 of 14 passes for 46 yards in a first half that ended with Colorado (0-1) trailing 20-3.

Dan Hawkins said he never considered pulling his son, blaming the lack of cohesion on penalties and mental mistakes: “When you’re three plays and out it’s hard for anyone to get rhythm.”

The Buffaloes looked like that had made the proper adjustments at halftime when they took the opening kickoff and needed just four plays to pull to 20-10 on Brian Lockridge’s nine-yard touchdown run.

Their momentum stalled, however, when wide receiver Scotty McKnight fumbled inside the Rams 20.