LSU reached No. 1 the hard way.

The Tigers edged past Southern California in the AP Top 25 on Sunday, even though the Trojans remained undefeated.

On a wild day in college football, when half the top 10 lost, USC avoided the upset bug that struck Oklahoma, Florida, Texas and Rutgers. But a sloppy 27-24 victory at Washington on Saturday night cost the Trojans the No. 1 ranking they’ve held all season.

USC is the first team to lose the No. 1 ranking after a victory since Nov. 3, 2002, when top-ranked Miami dropped after beating Rutgers 42-17 and No. 2 Oklahoma moved up after a 27-11 victory over No. 13 Colorado.

“I have no idea how the points work and how it all adds up,” USC coach Pete Carroll said Sunday night. “It has no bearing on anything for us. It didn’t before and it doesn’t now.

“The reason it happened is the way we played, I guess.”

LSU, which recovered from its own first-half malaise to beat Tulane 34-9 on Saturday, received 33 first-place votes from the media panel and 1,593 points. USC got 32 first-place votes, 11 fewer than last week, and 1,591 points.

LSU coach Les Miles suggested the voters didn’t get up early enough to watch the first half of the Tigers’ victory against Tulane, when they led 10-9 at the break.

“They kind of slept in and got kind of caught up on the score later in the day,” he said Sunday. “We can’t afford to play like that anymore for any length of time, whether it is a half or whatever. We played without the focus or intensity we are capable of.

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“There will be none of our players who arrive here on Monday that feel like they have achieved any milestone in any way. It will be business as usual.”

The voting was the closest since the second poll of the 2002 season, when Miami and Oklahoma tied for No. 1 and each received 27 first-place votes.

B.G. Brooks from The Rocky Mountain News in Denver had already flip-flopped USC and LSU once this season and went back to LSU again after watching the Trojans against Washington.

“I think at this point, at least through yesterday, LSU has been a little more dominant,” Brooks said.

LSU is No. 1 in the AP poll for the first time since Nov. 2, 1959.

Twelve voters switched off USC to LSU this week to swing the vote, though one voter, Jon Wilner of The San Jose Mercury News, voted USC No. 1 after having LSU last week.

“The main reason I did was because I look at LSU and USC and feel that the Trojans have two quality wins on the road and that tipped the scales toward SC,” Wilner said. “Winning in Lincoln and in Seattle gives them an edge over LSU’s two big home wins (over South Carolina and Virginia Tech).”

The rest of the rankings released Sunday bore little resemblance to any of the previous polls, thanks to a crazy weekend in which three of the top five and seven of the top 13 teams lost.

Overall, nine ranked teams went down, seven to unranked opponents.

California moved up three spots to No. 3, Ohio State jumped four places to No. 4 and Wisconsin moved up four spots to No. 5.