Alex Brandon, Associated Press
LSU's Glenn Dorsey (72), August Martin (27) and Tyson Jackson (93) help make up the No. 1 defense in college football.

BATON ROUGE, La. — At an oyster shack not far from the north shore of Lake Pontchartrain, a sign pokes fun at the defending national champion.

"Florida has sand and sun," it says, "but LSU is No. 1."

Yep, for the first time since 1959, the Tigers will run onto the field as the nation's top-ranked team. They'll be in for quite a prime-time reception at Death Valley, where raucous fans once caused earthquakelike readings on a seismograph.

"It's going to be awesome," LSU safety Craig Steltz said. "The crowd is going to be electric."

Atmosphere aside, don't count out that team on the visiting side tonight.

Florida, the wounded-but-still-standing titleholder, is eager to redeem itself for a stunning home loss to Auburn last week. The Gators can't afford another defeat if they're going to contend for another national title.

"I think every human being is measured when they get hit," said Florida coach Urban Meyer, who hasn't lost back-to-back games since he was at Bowling Green in 2002. "I tell people all the time: It's easy to walk upstairs, walk in my office and pick up that championship trophy. That's not hard. When you get hit right square, how do you react? We got hit square."

The Tigers (5-0, 2-0 Southeastern Conference) were actually pulling for a Florida victory last weekend, eager for a showdown between undefeated teams. That scenario didn't pan out. After rallying from a two-touchdown deficit, the Gators (4-1, 2-1) lost to Auburn on a last-play field goal.

"If they come in here undefeated and we're undefeated, the bigger the game is going to be," Tigers receiver Brandon LaFell said. "Still, that's Florida we're playing."

Surprisingly, LSU moved up to No. 1 by the narrowest of margins in The Associated Press Top 25, the beneficiary of Southern California's lackluster victory over Washington. The Trojans still hold the top spot in the coaches' poll.

The Tigers insist they're not worried about rankings as they approach the halfway point of the season.

"I'm pretty sure the fans are enjoying it," defensive lineman Glenn Dorsey said, "but it's just another day for us."

LSU is coming up on the one-year anniversary of a day it would prefer to forget. The Tigers haven't lost since a 23-10 setback at Florida on Oct. 7, 2006, winning 12 straight since.

Taking a page out of Florida's championship playbook, LSU has gone to a two-quarterback arrangement with starter Matt Flynn and backup Ryan Perrilloux.

Flynn handles most of the passing game — a la Chris Leak for the 2006 Gators — while the 6-foot-2, 227-pound Perrilloux plays the Tim Tebow role, essentially providing another running back when he's on the field.

Perrilloux is the team's fourth-leading rusher with 143 yards. He's also thrown for six touchdowns — three of them while starting against Middle Tennessee, when Flynn was held out because of a sore ankle.

Flynn, a senior, said he doesn't mind sharing time with the sophomore.

"If there's a weakness we can exploit with some quarterback runs, then, yeah, we're going to have that package in there," the starter said. "If it's working, I'm all for it."

Flynn, who backed up JaMarcus Russell while patiently waiting for his one year as the starter, shrugs off those who consider him the Tigers' weak link.

"It was tough playing behind JaMarcus," Flynn said. "But I always felt if I stuck it out, did the right things, that good things would happen. I feel really fortunate to be able to come into such a good situation."