Sam Darnold, both head coaches and everybody else in the Coliseum thought Darnold's wobbly pass was about to become Southern California's fifth turnover.
Everybody except Darreus Rogers, who simply went up and over Colorado cornerback Ahkello Witherspoon to steal it for a spectacular 46-yard gain .
"I never thought it was going to be a pick," Rogers said. "Those are the plays I need to make that will separate me as a player. I had to make that play for my teammates."
A few minutes later, the Trojans seized a victory they felt rightfully belonged to them, too.
Tyler Petite caught his second touchdown pass with 8:28 to play on a drive extended by Rogers' heroics, and USC overcame four turnovers to beat No. 21 Colorado 21-17 on Saturday.
Daniel Imatorbhebhe also caught a TD pass from Darnold, who passed for 358 yards and three scores along with two fumbles and an interception. USC (3-3, 2-2 Pac-12) shredded one of the nation's top defenses for 539 yards, but Colorado's takeaways kept an otherwise one-sided game close.
"All Pac-12 wins seem hard, especially when you turn the ball over like we did," USC coach Clay Helton said.
After dominating for long stretches ruined by turnovers, the Trojans finally made their own breaks. Adoree Jackson made a jaw-dropping, one-footed interception , but the game turned on Rogers' unbelievable effort.
"I thought Ahkello had a pick," Colorado coach Mike MacIntyre said. "It was right in front of us. He goes over and pulls it out of his hands, and it was a great play by their receiver. When the kid threw it, I thought, 'I'm glad he threw it. I think we got us another pick.' And then all of a sudden, what a great play."
Helton also was sure Darnold's pass would be intercepted by Witherspoon.
"He had two hands on it, and I had one hand," Rogers said. "I felt like if I tucked it in faster, I could take it off of his hands. I wanted it more."
After Petite's tiebreaking score , Colorado (4-2, 2-1) kicked a field goal with 4:49 left, but the Trojans coolly ran out the clock. JuJu Smith-Schuster slid to the turf with a clear lane to the end zone and 1:15 to play, allowing USC to kneel it out.
In the Buffaloes' first game as a ranked team since Nov. 7, 2005, receiver Bryce Bobo threw a 67-yard touchdown pass in the third quarter and caught a tying TD pass with 10:20 to play.
Colorado fell to 0-11 in school history against USC in a rivalry dating to 1927.
"Somehow, some way, we've got to get USC," MacIntyre said. "We're 0-fer right now. We've got to get that off our back. We'll do that eventually."
Justin Davis rushed for 83 yards before leaving with a high ankle sprain early in the second half for USC. Davis left the stadium on crutches.
Steven Montez passed for 197 yards in the freshman's third straight start. Colorado career passing leader Sefo Liufau also played briefly, but he can't run much on his injured ankle, MacIntyre said.
"Today was just a testament to how much work we have left," Montez said. "It's a humbling experience to show that we weren't what we thought we are, and have so much work to do. I think it will help us in the long run. It will keep us hungry and get us focused."
Colorado: The Buffaloes' return to the AP Top 25 after an 11-year absence could be over after one week after losing to a .500 opponent, but they'll have a chance to return quickly.
Colorado: The Buffaloes have plenty of work to do if they want to stay on top of the Pac-12 South standings. USC exposed deficiencies on both sides of the ball, but the Buffs' opportunistic defense kept it close and suggested that this long-downtrodden program can hang with anybody.
USC: After going 1-3 in a brutal September schedule, USC has been largely outstanding against two Pac-12 opponents in October. Helton surely will emphasize ball security in the upcoming week, because it's the only thing that kept this win from being a second straight blowout of a division foe.
Colorado: The Buffs are back in Boulder to host Arizona State in another key Pac-12 South showdown.
USC: The Trojans head out for their only road game of October, traveling to Arizona.