PASADENA, Calif. -- When Anthony Barr roared through the line and hit Matt Barkley squarely in the No. 7 on his back, the roar rising out of the Rose Bowl was loud enough for a whole city to hear.

After so many years underneath Southern California, UCLA is on top of Los Angeles and the Pac-12 South, thanks to a first-year head coach and a freshman quarterback who don't realize they've done something that's not usual.

"Well, it is for me," Jim Mora said.

Brett Hundley passed for 234 yards and a touchdown and rushed for two more scores as No. 17 UCLA beat USC (No. 18 BCS, No. 21 AP) 38-28 on Saturday, clinching the Pac-12 South title and emphatically snapping a five-game losing streak in their crosstown showdown.

Eric Kendricks blocked a punt and made a fourth-quarter interception for the Bruins (9-2, 6-2 Pac-12), who overcame intermittent second-half rain and USC's star-studded lineup with a steady effort.

"When the season started, obviously nobody thought we were going to do what we're doing now," said Hundley, who was 22 of 30 and didn't throw an interception. "But we all knew deep down inside that we could do it, that we had the talent. We can do everything we set our mind to as long as we work hard."

Barkley, meanwhile, left the game with an apparent shoulder injury after Barr's sack and did not return.

He talked to the media after the game with his right shoulder hidden inside a sweater. The shoulder appeared to be supported by a sling. Barkley declined to discuss the injury, citing the program's policy on not disclosing injuries, and answered only three questions in an abbreviated news conference before being whisked away to the team bus by a school spokesperson.

"I thought I fought as hard as I could've fought," Barkley said. "I went down fighting. Plays were there, plays weren't there. There were times where I felt like I could've broken the game open. It just didn't happen."

A year after USC obliterated the Bruins 50-0 in a game that led to a coaching change in Westwood, UCLA punctuated its one-year revitalization under Mora with its first win over the Trojans (7-4, 5-4) since 2006 -- just their second in 14 years. The Bruins celebrated in the corner of the Rose Bowl and again with an impromptu dance-off in the locker room, even while Mora reminded them they've still got three games to play.

"It's a great moment, and I'm excited," said Mora, the winningest first-year coach in UCLA history. "I can't wait to hug my mom, shake my dad's hand and kiss my kids. I don't want to minimize it at all."