The Pac-10 season kicks into gear this weekend with a duel for first place between ... No. 24 Washington and Stanford?

The Pac-10 season kicks into gear this weekend with a duel for first place between ... No. 24 Washington and Stanford?

Meanwhile, bottom-feeders Washington State and Southern California square off in Los Angeles.

It's early, but the 12th-ranked Trojans' stunning 16-13 loss in Seattle last weekend has flipped the Pac-10 upside-down.

"We all, I think, give USC their due credit for being the favorite, but with an early loss like that, and the fact that I think there's a lot of improvement generally in the league from top to bottom, it's going to be very interesting week to week," Oregon State coach Mike Riley said on Tuesday.

On second thought, it may be time to retire the word "stunned" in stories about USC defeats in the Pac-10. If the Trojans are stunned, they haven't been paying attention.

The loss at Washington followed a pattern that began in 2006. USC lost two Pac-10 games that year, and the second one, at UCLA, cost the second-ranked Trojans a shot at the Bowl Championship Series title.

In 2007, No. 2 USC lost to 41-point underdog Stanford, at home. (OK, that was stunning.)

In 2008, the top-rated Trojans lost their conference opener at Oregon State.

In each case, the Trojans managed to bounce back and claim a conference title, but they were denied a shot at the national championship.

Those USC teams had John David Booty and Mark Sanchez at quarterback, and a defense loaded with future NFL draft picks.

This USC team has struggled to move the ball behind two relatively inexperienced quarterbacks — sophomore Aaron Corp and true freshman Matt Barkley, who missed the Washington game with a bruised shoulder. Meanwhile, All-America safety Taylor Mays has a sprained right knee ligament and didn't play against the Huskies.

Add it all up and it appears that the Trojans' record seven-year run of Pac-10 titles could be in jeopardy. The remaining schedule is rugged, with trips to No. 6 California on Oct. 3 and to Oregon on Oct. 31.

"There's this image out there that USC has a reputation for not showing up once a year, when the reality is that the conference is deep," Pac-10 commissioner Larry Scott said in a recent telephone interview.

Indeed, USC is 30-1 against the nation, and 15-1 against ranked non-conference teams, since a loss to No. 25 Kansas State in 2002. The lone loss in that span came in the thrilling 2005 BCS title game against Texas and Vince Young.

By contrast, USC is 52-8 in Pac-10 games since 2002.

The conclusion: Pac-10 teams have figured out how to play the Trojans.

Washington coach Steve Sarkisian, who served as an assistant to USC coach Pete Carroll before taking over in Seattle, has been on both sides of a headline-grabbing USC loss.

"I think a lot of the kids within this conference that aren't at SC are used to these kids," said Sarkisian said. "They've known these kids (in high school). They're not in awe of them. They just go play."

USC tailback Joe McKnight offered a similar take after the loss. "Washington wasn't the better team; they just outplayed us," he said. "Clearly, we have superior athletes. But hard work beats athleticism any day."

Sarkisian may have had an edge against USC because he served on Pete Carroll's USC staff for seven seasons — the last two as offensive coordinator — before taking over in Seattle. Sarkisian's departure was a double blow for the Trojans, because he took defensive coordinator Nick Holt with him.

Sarkisian had a good idea about what USC was going to run and how to stop it. Strategy alone won't erase a wide gap in talent, but it can help.

"I do think familiarity in the league is going to make it tough for SC," said Riley, whose Beavers have beaten USC two of the last three years. "Everybody's going to give them a great shot. The beautiful thing is, as good as they are, there are no givens. That's why we play the games."

Carroll pointed to a different link among USC's recent conference losses: carelessness with the football. The Trojans turned the ball over three times inside the Washington 35-yard line on Saturday.

Knocking off the Trojans may be an annual rite in the Pac-10, but it's still a big deal on every campus, especially at Washington, which went 0-12 last year. On Washington's Web site, the athletic department is selling framed photos from last weekend's game, including a picture of the Husky Stadium scoreboard: HUSKIES 16, TROJANS 13.

As the conference season unfolds, the question is whether the Huskies' victory was a fluke, or whether it revealed real cracks in the Trojans dynasty.

A year ago, USC rebounded from a 27-21 loss at Oregon State to hammer Oregon, Arizona State and Washington State by a combined 141-10.

USC didn't lose again for 353 days — until last Saturday, at Washington.

Stunning? Nope.

"This league has shown that everybody is capable, everybody is vulnerable, and every week you've got to prepare," said Stanford coach Jim Harbaugh, whose Cardinal knocked off the Trojans in 2007.