USC’s reign as college football’s No. 1 team lasted as long as it took the Trojans to play a game.

The Trojans dropped one spot, to No. 2, Tuesday in the Associated Press media poll. Yet, in the USA Today coaches’ poll, USC moved up a notch, from No. 3 to No. 2 — for the same 49-10 victory over Hawaii.

Welcome to poll vaulting at the 2012 BCS Olympics. This, folks, is one reason why we’re going to a four-team playoff in 2014.

This just shows how silly polls can be and why they have been, for decades, a hilariously unreliable way to pick champions.

To recap: USC started the season No. 1 in the preseason AP poll and opened with a resounding 39-point win over Hawaii at the Coliseum.

Three days later, USC fell to No. 2 in the AP poll. Maybe the writers weren’t happy the Trojans failed to cover the 40-point spread? Have you ever seen a writer who just lost a bet?

“It doesn’t matter,” USC quarterback Matt Barkley said. “I don’t care. A ranking doesn’t motivate me. I think being perfect is what motivates us. And the rankings and all that other stuff will fall into place.”

Someone needs to tell Barkley about USC and 2003.

Top-ranked in both polls Tuesday was Alabama, which dominated previously No. 8 Michigan, 41-14, in its opener at Arlington, Texas.

“I would agree with that,” USC Coach Lane Kiffin said. “I didn’t watch any of the game . . . but from what I’ve heard they played a really good Michigan team in a big matchup and played really well, so whatever. Don’t care.”

Part of the problem is that AP voters and coaches based moving Alabama to No. 1 on the possibly fraudulent premise that Michigan was good.

USC isn’t the only team mumbling. Louisiana State got bounced from No 1 to No. 3 in the coaches’ poll after a 41-14 win over North Texas. Part of that, though, was coaches’ self-correcting after the suspension of star Tigers cornerback Tyrann Mathieu.

Bottom line: there was no credible reason to drop two No.1 teams in one day after 39- and 27-point wins.

Voters should allow at least a two- or three-week adjustment window. Wait for USC to struggle to victory on the same weekend Alabama wins big. That could happen as soon as Sept. 15, when USC plays at Stanford the same day Alabama plays at Arkansas.

What does the early drop mean for USC?

Standing at No. 2 in the USA Today poll is more important than being No. 2 in the media poll. The AP is no longer a part of the BCS formula, whereas the coaches’ index is one of the three components that will be used in determining the two participants in the BCS title game.

There is no reason (yet) to think USC has to pound Syracuse so badly in New Jersey on Saturday that they’ll be able to hear the yelps at AP headquarters in New York City. As USC discovered in 2003, though, there comes a time when coaches and players who say they don’t care about polls get real interested, real fast.

But for now, condolences/congratulations to USC for Tuesday’s flummoxing poll fluctuations. It certainly is a troubling/promising situation.

chris.dufresne@latimes.com

Times staff writer Gary Klein contributed to this report.