EUGENE, Ore. — This was the day.

This was the spot for USC's runaway train to fall off the tracks. This would be the day Reggie Bush morphed from celestial to mortal, the day starlets turned their back on Matt Leinart and said "Uh-uh."

Right.

When it was done, and a state-of-Oregon record crowd of 59,129 filed glumly out of Autzen Stadium, USC had throttled Oregon 45-13.

For all the love the Trojans got from every precinct, national and regional, for their 70-17 whacking of Arkansas last week, this latest victory — a Pac-10-record 25th in succession — was much more telling.

All USC did was go into the consensus most prickly environment in the Pac-10, look like the Trojans under Paul Hackett for 22 minutes in falling behind 13-0, then flick aside a pretty capable Oregon team with a cascade of 45 straight points.

"They're not what they're advertised," Oregon receiver James Finley said grudgingly. "They're good, but I mean... "

You could have fooled us.

In a nutshell, this was what USC did: Favored by an Autzen-record 21 points (for an opponent), it played miserably until midway through the second quarter, and still lived to dominate. The Trojans had it both ways: They strafed Oregon for 593 total yards, and they got a strong effort on defense, which is their supposed weakness.

"Their team speed," said Oregon quarterback Kellen Clemens, "was at a whole 'nother level."

Then they slogged through a scoreless first quarter against the Ducks, who didn't do anything cosmic defensively, except occasionally disguise coverage and mostly rush four at Leinart. Without a lot of pressure, he sometimes looked flustered, enduring a 6-for-13 first quarter for 78 yards.

It was the Trojans who brought the heat, throwing a more-frequent blitz at Clemens, and when they didn't, usually running "twists" by their defensive linemen.

USC was awash in mistakes, turning a touchdown catch into an interception and sampling a smorgasbord of nine penalties in the first half, most of them majors. It was displeasing to everybody on the USC sideline, including Trojans fan Jessica Simpson.

Turns out, the guy who might have kept USC unbeaten was one of the least-heralded players on the roster. That's David Kirtman, the six-foot, 230-pound senior fullback from Mercer Island High, who had all of 13 career carries, none this year.

This was the setup: The Ducks had a 13-0 lead nearing the midpoint of the second quarter, the USC deficit equaling its largest all last year.

The Trojans faced third-and-20 at their 45-yard line. If there's such a thing as a gut-check around Heritage Hall these days, this was it.

Leinart floated out a pass in the deep right flat to Kirtman, and at first, it looked more hope than promise. But Kirtman, needing to run for perhaps 8 yards for the first down, kept plugging, carrying cornerback Aaron Gipson and linebacker Chris Vincent past the marker by a yard at the 34. A few plays later, USC was in the end zone.

Get this: The key block for Kirtman came from Reggie Bush.

"I was just open," said Kirtman. "Reggie made a good block. I just tucked my shoulder and ran people over."

"I don't know if it was a good block," Bush said with a shrug. "But I tried to do what I could.

"Kirtman is a warrior."

It was 13-10 at halftime, Oregon, then stuff like this happened: Bush squirted for 38 yards on the second play after intermission. Leinart threw to Dwayne Jarrett for the go-ahead touchdown. Bush juked his own shoe off, and still left Gipson flailing on a 12-yard run.

Defensive end Lawrence Jackson thundered in atop Clemens before he could throw. Bush, trapped while fielding a bouncing punt at his own 12, somehow bisected two defenders and returned it 24 yards. Then this: Leinart, not to be confused with Michael Vick, dodged linebacker A.J. Tuitele into another county on a 20-yard scramble.

If we learned anything, it was that you have to cold-cock a champion, not body-punch him. The Ducks settled for two first-half field goals and after a second-and-one chance at the USC 20, Paul Martinez missed another one badly two plays later.

Had the Trojans gotten behind by three scores, you had the sense it might have gotten interesting.

Either that, or USC would have won 45-17.

Bud Withers: 206-464-8281 or bwithers@seattletimes.com