In the final two minutes, CU still had an outside at the win, but needed two late touchdowns. They came close to getting one of them, but confusion ended a late drive.
On third-and-10, Steven Montez completed a 9-yard pass to Jay MacIntyre to the USC 3. MacIntyre was about a foot short of the first down, creating a fourth-and-1 situation. The sticks on the west side of the field showed first down, however, and Montez thought he had four plays to go.
He was pulled down for a 5-yard loss on the next play, and CU turned the ball over on downs.
"I'll be dead honest with you, I definitely thought it was first down," Montez said. "I thought Jay MacIntyre got the first down when we threw it to him. Some of the coaches were saying that they knew it was fourth down and we were just trying to crash it in there.
"USC brought a zero pressure. It was smart on their part. They caught us. They knew it was fourth down."
Oliver returns and then leaves
Junior cornerback Isaiah Oliver returned to the lineup after missing the previous two games with a leg injury, but wasn't himself and didn't play in the second half.
"He said he was 100 percent and the doctor said he was 100 percent, but he didn't play quite like Isaiah," coach Mike MacIntyre said. "I guess he wasn't 100 percent mentally. That's always tough when they come back and they're playing really talented receivers and a really talented quarterback. They can kind of exploit that.
"He's a great player and he tried to fight through it and wasn't able to go in the second half. We'll see how he's able to hopefully bounce back and play against Utah."
In addition to losing Fields and Oliver, the Buffs played without senior safety Ryan Moeller (leg).
USC blocked two field goals in a game for the first time since its 2011 visit to Boulder. ... Phillip Lindsay scored his 35th career rushing touchdown, second-most in CU history behind Eric Bieniemy (41). ... During senior day festivities, walk-on linebacker Trent Headley proposed to his girlfriend, a CU cheerleader. She said, "Yes." ... There were 18 scouts from 13 NFL teams in attendance for Saturday's game. ... Attendance was 49,337, the second-best total of the season and third-best in MacIntyre's five seasons. ... Average home attendance for the season wound up being 47,056, the best at Folsom Field since 2011.