Another year, another set of lofty expectations for Southern California .

The top-ranked Trojans begin their quest to reach the Bowl Championship Series title game for the fourth time in five years Saturday when they play what appears to be a vastly overmatched team from Idaho .

Pete Carroll's team was in line to play in the title game last year until a surprising 13-9 loss to UCLA in the season finale. You can purchase USC Trojans vs UCLA Bruins Tickets The Trojans' first two-loss season since 2002 relegated them to the Rose Bowl, where they defeated Michigan to wrap up a fifth consecutive year with at least 11 victories.

Southern California is 59-6 over the last five years, having won the Bowl Championship Series titles in 2003-04, and losing another in 2005. The Trojans also won BCS games in 2002 and 2006, making them arguably the closest thing to a college football dynasty since Nebraska from 1994-97.

This year, Southern California - the preseason AP No. 1 for the third time in four years - is an overwhelming favorite in the Pac-10. Fifth-year senior quarterback John David Booty is being touted as a Heisman Trophy candidate after throwing for 3,347 yards and 29 touchdowns last season, and the Trojans have amassed a stable of highly touted running backs.

"He's a natural-born quarterback," Carroll said of Booty, who could be the third Trojans quarterback to win the Heisman in six years, following current NFL starters Carson Palmer and Matt Leinart . "He's got five years of experience. He's been through everything you need to be good."

The team's depth at tailback will come into play, as starter Chauncey Washington, who had a team-high 744 yards in 2006, will miss this game due to a sprained right shoulder. Carroll plans to start sophomore C.J. Gable , while Allen Bradford , Stafon Johnson and freshman Broderick Green could also see time.

Carroll also hopes to use highly regarded freshman back Joe McKnight, who was just cleared for contact after missing two weeks with a stretched knee ligament, in the backfield.

"There's no part of me that wants to hold him back,' Carroll said of McKnight. "We'd love to play him.'

While the offense can strike quickly, the Southern California defense strikes fear into opponents. The Trojans have one of the nation's best linebacking corps with Brian Cushing, Keith Rivers< and Ray Maualaga, while defensive end Lawrence Jackson and tackle Sedrick Ellis anchor the front line.

"We have a lot of experience and tremendous speed," Carroll said. "We'll find out how good they are when we start playing."

Despite the mismatches at seemingly every position, the Trojans, who are listed as favorites by more than six touchdowns, insist they are focused on the task at hand - beating Idaho - before looking ahead to what likely will be a more difficult game Sept. 15 USC Vs Nebraska.

"If you take any team lighter than another team, your focus is wrong,' said center Matt Spanos, a fifth-year senior who will be making his first career start against the Vandals. "We prepare for everybody the same.

"We don't go into any game thinking ahead of ourselves. It's just like that in life - you've got to live in the present.'

The Trojans, who have won five straight Pac-10 titles, also are riding a school-record 33-game home winning streak.

The Vandals' Robb Akey could not have asked for a more difficult head coaching debut. He arrived in Moscow, Idaho, after spending eight seasons as an assistant with Pac-10 rival Washington State. The Vandals lost their final five games - getting outscored 217-56 - last year to finish 4-8, good for sixth place in the Western Athletic Conference.

Idaho is essentially starting from scratch offensively. Redshirt freshmen Nathan Enderle and Deonte Jackson will make their collegiate debuts while playing quarterback and tailback, respectively, and the defense has been ahead of the offense leading up to this game.

"Our defense did a good job of flying around," Akey said after an Aug. 18 scrimmage. "I like the progress we've made. We certainly still need more but I do like where we are."

The defense is led by senior linebacker David Vobora, an first team all-WAC selection last year after leading the conference in tackles and tackles-for-loss.

Southern California has outscored Idaho 215-20 in winning all seven games between the schools, which are playing each other for the first time since 1929.