updated 2:49 a.m. ET Sept. 30, 2007

The national title race received a major makeover in an upsetting couple of days for a bunch top-ranked teams.

Half of the top 10 teams in the country lost in the fifth weekend of the season, including defending national champion and fourth-ranked Florida falling 20-17 at home to Auburn on a last-second field goal.

No. 3 Oklahoma, No. 7 Texas, No. 10 Rutgers and No. 13 Clemson were also all handed their first losses Saturday ... all by unranked opponents.

Add to that No. 5 West Virginia’s 21-13 loss to No. 18 South Florida on Friday night, plus No. 6 California knocking off No. 11 Oregon 31-24, No. 21 Penn State falling to Illinois 27-20, and No. 22 Alabama getting knocked off by Florida State 21-14, and it’s pretty obvious the polls will have a very different look Sunday.

Except at the very top, though even that looked shaky for a while Saturday night.

No. 1 Southern California overcame its own sloppy play — the Trojans had 16 penalties, three turnovers and a blocked punt — and escaped Washington with a 27-24 victory.

It was the first time since the weekend ending Oct. 12, 2003, that five top-10 teams lost in the same week. No. 3 Ohio State, No. 5 Florida State, No. 6 LSU, No. 7 Arkansas and No. 10 Nebraska were the losers in 2003.

This latest wild Saturday was capped by Auburn, which snapped the Gators’ 11-game winning streak.

“It’s very disappointing,” Florida coach Urban Meyer said. “We didn’t play smart.”

The Tigers had a 17-3 lead in the second half, but Tim Tebow led Florida back to tie it in the fourth quarter.

In the end, though, it was Auburn’s Brandon Cox, benched earlier this season as the Tigers’ offense struggled, who came up big in the clutch.

Cox passed for 227 yards and directed a 4-minute drive that put Wes Byrum in position for a 43-yard field goal. The freshman kicker made it, twice. The first time he sent the ball through seconds after Florida called a timeout to ice him. His next try was even straighter than the first.

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“It doesn’t get any better than that,” said Byrum.

The loss could jeopardize Florida’s chances of repeating. Then again, with all the other upsets Saturday, the Gators surely won’t slip too far out of the picture, especially if they can beat No. 2 LSU next week.

Oklahoma was first to go down Saturday, falling to three-touchdown underdog Colorado on Kevin Eberhart’s 45-yard field goal on the last play of the game.

“They outplayed us and outcoached us,” Oklahoma coach Bob Stoops said. “They fought their way to a heck of a win.”

The Sooners had looked all but unbeatable through four games, scoring at least 50 points in each and never being tested.

In the second year of rebuilding under coach Dan Hawkins, the Buffaloes took the Sooners’ best shot and didn’t back down in Boulder. Oklahoma led 24-7 in early in the second half and didn’t score again.

Oklahoma redshirt freshman Sam Bradford, who had been close to perfect in the first four starts of his career, was 8-for-19 for 112 yards and two interceptions against a tough Colorado defense that Stoops had praised all week.

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Cody Hawkins, the coach’s kid, led the Colorado rally, throwing for 220 yards and two touchdowns.

“You guys all think I’m joking, but there wasn’t anybody inside that locker room that thought we were going to lose that game,” Hawkins said.

As if Oklahoma losing wasn’t enough to take the juice out of next week’s Red River Rivalry game against Texas, the Longhorns followed the Sooners’ loss with one of their own to another team from the Big 12 North, the conference’s weaker division for the past several years.

Kansas State beat the Longhorns for the second straight season, this time in Austin.

The Wildcats had three touchdown returns — Ian Campbell’s 41-yard interception, James Johnson’s 85-yard kickoff return and Jordy Nelson’s 89-yard punt — and they knocked around Longhorns quarterback Colt McCoy in a 41-21 victory.

Call it an upset, but Texas had looked primed for a beating during its 4-0 start, with shaky victories against Arkansas State and Central Florida.

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