BERKELEY, Calif. (AP) The fortunes for Southern California and California have undergone quite the change the past two weeks.

Back-to-back losses by the Golden Bears (5-2, 2-2 Pac-12) have erased the good feeling from a 5-0 start and have raised questions about whether Cal is in for another late-season flop.

USC (4-3, 2-2) rebounded from the firing of coach Steve Sarkisian and three losses in a four-game span to hand Utah its first loss last week in a performance that validated the preseason hype around the Trojans.

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If a topsy-turvy season in the Pac-12 has proved anything so far, it's that perceptions can change quickly. The Trojans will look to avoid that roller-coaster when they visit the Bears on Saturday.

''We're an ultra-talented conference,'' USC interim coach Clay Helton said. ''You have to bring your `A' game every week. You have to treat every game like a championship game because if you have an off-day, you'll get beat, as proven in this league.''

USC has been able to do that over the years against Cal, dominating this in-state rivalry for more than a decade. The Trojans have won 11 straight meetings against the Bears since a triple-overtime loss in 2003.

Most of those haven't even been close with the average margin of victory being nearly 19 points. Last year's 38-30 USC win was the closest since 2007 but only got that way when Cal scored two late touchdowns long after the game had been decided.

This marks the second straight season that Cal got off to a fast start against the easy part of its schedule only to fall flat when the games got tougher in the conference season. The Bears started 4-1 a year ago, only to lose six of their final seven games to fall one win shy of a bowl bid.

''When you play against good teams, your level of execution has to go up,'' coach Sonny Dykes said. ''We probably haven't raised our level of execution as much as we need to.''

Here are some other things to watch when USC visits Cal:

TOP FLIGHT QBS: With Cal's Jared Goff and USC senior Cody Kessler, this game features two of the top passers in the country. Kessler is completing more than 69 percent of his passes with 18 TDs and five interceptions. Goff has completed 65.5 percent of his passes with 20 TDs and nine interceptions but is coming off his two worst games of the year, including a five-interception performance against Utah three weeks ago.

''We have to be able to run the ball better,'' Dykes said. ''That will take a little pressure off of him. We just have to execute better as a group. It's not just Jared. It's really our offense.''

CENTER OF ATTENTION: The Trojans are on their third starting center after losing Max Tuerk and Toa Lobendahn to season-ending injuries. Khaliel Rodgers stepped in last week against Utah after Lobendahn left in the first quarter and fared well. Now he gets the start.

''I was ready last week, and I'm ready for this week,'' Rodgers said. ''An opponent is an opponent. I don't look at it as any different. You just have to wait until your time comes, and now it's time to go out there and perform.''

REELING VS. RIVALS: Cal has had trouble against a lot more teams than just USC. In fact, the Bears have not beaten any of their three conference in-state rivals since Dykes took over in 2013, losing three times to UCLA and twice each to Stanford and USC. In all, Cal has been outscored 314-156 in the seven losses.

FABULOUS FRESHMAN: USC freshman linebacker Cameron Smith is coming off a breakthrough game with three interceptions, including one returned for a touchdown in the win over Utah. But Smith has been impressing the Trojans ever since he joined the program as an early enrollee last winter.

''He's just been a pain in our butt offensively,'' Helton said. ''He gives Cody Kessler headaches week in and week out. We saw it early. He's such a football instinctive kid.''

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AP Sports Writer Greg Beacham in Los Angeles contributed to this report.