Top-ranked Southern California laid out its case for the national championship the best way it knew how — by dominating No. 4 Michigan with a 28-14 victory Thursday in the Rose Bowl.

Matt Leinart threw three touchdown passes and caught another to lead the Trojans past the Wolverines with a performance so persuasive that voters almost certainly will leave USC atop the poll.

The Associated Press’ No. 1 team has never dropped in the rankings after winning its bowl, and it doesn’t look as if it will happen this time, either.

“I think we just won the national championship,” jubilant USC coach Pete Carroll said. “I think it’s clear that we did everything we needed to.”

While the Trojans, who rank third in the Bowl Championship Series standings, are primed to win their first title in 25 years, they would have to share it. Voters for the USA Today/ESPN coaches’ poll are obligated to crown the winner of Sunday’s Sugar Bowl between No. 2 Louisiana State and No. 3 Oklahoma, playing in the BCS championship game.

“He won a national championship, I’m sure of that,” Michigan coach Lloyd Carr said, referring to Carroll.

The Trojans were left out of the BCS title game because of an early-season loss to California and a weaker schedule, but they felt right at home in front of a sellout crowd of 93,849.

Leinart, the game’s MVP, shredded the nation’s sixth-ranked pass defense for 327 yards, and the Trojans (12-1) had a season-high nine sacks and even blocked a field goal by Michigan (10-3).

The signature play came late in the third quarter when Mike Williams took a reverse handoff from Hershel Dennis and flicked an easy pass to Leinart, who jogged in for a 15-yard score that made it 28-7.

With the big lead, all the Trojans needed to do was run out the clock — and start waiting for the final AP poll early Monday morning. The fans had their answer already, chanting “We’re No. 1! We’re No. 1!” during the final minutes.

After the clock ran out, Carroll jumped around hugging players as star-shaped confetti rained down. The Trojans then gathered in the corner of the end zone to pay tribute to their band and fans.