CORVALLIS, Ore. — Could we possibly have been that wrong?

Did USC simply fool us?

Are Virginia and Ohio State that bad?

Either a bunch of impostors wearing cardinal, gold and white showed up at Oregon State's Reser Stadium on Thursday night, or the Trojans revealed their true colors.

USC's outlook-altering, 27-21 defeat didn't stem from Trojans mistakes like the last time they lost here, in 2006. No, this was different. This was about fundamentals such as tackling and blocking.

This was about battles lost at the line of scrimmage. This was disturbing.

"They played better than us," USC coach Pete Carroll said afterward in a cramped hallway underneath Oregon State's basketball arena. "They played harder than us.

"They didn't hide what they were doing. They just did it, and we couldn't stop them."

The most unstoppable Beavers player of all was tailback Jacquizz Rodgers, a 5-foot-6 freshman whom the Trojans let slip through their grasp time and again.

Rodgers was the just the 10th player in the past 77 games to rush for 100 or more yards against USC — and he did that in the first half. Rodgers finished with 186 yards against a USC defense that had allowed 103 in its first two games, a pair of victories by a combined score of 87-10.

USC thought it might have a bead on Rodgers thanks to its own diminutive freshman tailback, Curtis McNeal, who arrived just in time after getting through the NCAA academic clearinghouse to serve as a Rodgers impersonator in practice. Oddly, though, McNeal wore No. 8 for those scout-team sessions — the number of Rodgers' brother, slotback James Rodgers. Jacquizz Rodgers is No. 1. USC won't be for very long.

How far the Trojans tumble in the rankings was among many lingering questions as they dressed quietly in the visitors' locker room.

USC was a near-unanimous No. 1 choice in the writers' and coaches' polls after smashing then-No. 5 Ohio State, 35-3. Pundits portrayed the Pac-10 as the Pac-1 and nine also-rans. The talk-show talk wasn't about Oregon State; it was about whether USC somehow could lose a spot in the BCS title game despite going undefeated in conference play, the conference supposedly weak enough to drag the Trojans down with it.

A perfect, dominant run through the Pac-1+9 was behind a likelihood; it was a certainty.

Then Oregon State happened, again.

"The reality of the Pac-10 is obvious," said Carroll, who had insisted all along that rumors of the conference's demise were greatly exaggerated.

Carroll believed he had his team prepared for a prime-time visit here, dismissing talk of a letdown and ignoring the ghosts of Corvallis past. Then the game started, and USC didn't look prepared at all.

"When we were out there," Carroll said, "it just didn't feel like it."

USC didn't bring a split squad to Corvallis; it brought a split personality.

During the first 30 minutes, the Trojans didn't look like they belonged on the same field with the

Beavers. One scribe in the press box said he was counting the number of USC players on the field on each play to make sure there were 11. Carroll should have considered checking IDs.

Then, during the next 15 minutes, the Trojans suddenly looked like themselves again. They flew to the ball on defense. They gained first downs and scored touchdowns on offense. Carroll is renowned for his halftime adjustments; it appeared he had made all the necessary corrections.

But the hole USC found itself in proved too deep, a common thread with that 33-31 upset loss here in '06. The Trojans fell behind then, 33-10, and their unbeaten season died when a potential tying two-point conversion got batted down.

USC lost one more game that season, to UCLA, but won the Rose Bowl and finished No. 4 in the final rankings. The Trojans will have to readjust their expectations in 2008.

Reaching the BCS title game is still possible; heck, LSU made it with two losses last season. But the

SEC's power ranking is much higher than the Pac-10's, even if the conference is better than people think. USC has lost any margin for error it might have had.

The Trojans did not expect to be caught in traffic outside of Los Angeles, but there they were, fighting through streams of orange-clad Oregon State fans who swarmed the field.

The public-address announcer repeatedly urged the fans to stay classy, Corvallis, but it was a fruitless plea. As he repeated his message in the final minutes, hundreds of students already had jumped the wall behind the Oregon State bench.

No one could stop the students, just like the Trojans couldn't stop Jacquizz Rodgers, not early and not late, when his plowing 2-yard plunge bumped the score to 27-14 and sent Oregon State's fans into a frenzy of leaps and hugs.

What Oregon State did to USC was nothing new. "They've been running those plays for how many years now?" linebacker Brian Cushing asked. The way USC lost was unfamiliar. And more than a little worrisome.