SANTA CLARA, Calif. – Despite a second-half rally that had No. 20 USC leading No. 7 Stanford in the third quarter, the 2015 Pac-12 Football Championship title was not meant to be for Clay Helton in his first outing as the Trojans' permanent head coach.

An inopportune turnover, combined with an unstoppable Christian McCaffrey-led Stanford offensive attack, saw the Cardinal pull away in the fourth quarter and win the game, 41-22, Saturday night in Levi's Stadium.

Roars of angst from the USC coaches' box were audible in the adjacent press box as McCaffrey racked up a personal, Stanford football, and Pac-12 Football Championship single-game record 461 all-purpose yards.

"He's as special a player as we've seen all season," Helton said of McCaffrey. "His ability to break tackles is what stood out today. We've talked about gang-tackling him all week... He's a mismatch nightmare when you play man to man."

Despite McCaffrey's greatness, USC was very much in this game deep into the second half. A Cody Kessler TD pass to Jahleel Pinner coupled with a 27-yard TD rush from Ronald Jones had the Trojans ahead, 16-13, with 5:28 remaining in the 3rd quarter.

It was the only lead the Trojans would enjoy, as a Stanford's Kevin Hogan and McCaffrey combined for three more touchdowns while the Cardinal defense stiffened. And despite USC's deep ball weapons in JuJu Smith-Schuster and Darreus Rodgers, the Trojans' longest passing play only went for 22 yards.

"They did a good job of playing their safties deep, and they did a good job of getting pressure on me," Kessler said of the Trojans' lack of a deep threat. "It made it hard for the longer routes to develop. We had to deal with what they were giving us."

When Steve Sarkisian was terminated as USC head coach on Oct. 12th with a 3-2 record, many believed that a Trojans appearance in the Pac-12 Football Championship was, at best, wishful thinking. But "Fight On" they did. Under Helton, the Trojans went on to finish the season 6-2, and earned their interim coach a permanent job in the process.

Low-and-behold, here they were in Santa Clara, and here they competed til the end on the big stage.

What's next for the Trojans?

"I look forward to having a tremendous bowl game with a bunch of our seniors who have helped us get to this point," Helton said.