LOS ANGELES — In what's been the year of the upset in college football, Stanford's stunner just might top them all.

Tavita Pritchard threw a 10-yard touchdown pass to Mark Bradford on fourth-and-goal with 49 seconds remaining last night, giving the 41-point underdog Cardinal a 24-23 victory over No. 2 Southern California.

A leaping Bradford caught the ball over cornerback Mozique McCurtis in the corner of the end zone, leaving the crowd of 85,125 at the Los Angeles Coliseum in stunned silence. Bo McNally's interception thwarted USC's final chance.

In a season that started with Appalachian State's improbable victory over Michigan at the Big House, and a week after half the top 10 went down, the Cardinal are now the upset kings — at least for now. The way things have been going, that could change next week.

Making his first career start, Pritchard had to convert on fourth-and-20 four plays before the winning TD, and because he couldn't hear his coach calling in the play, he was on his own.

"I think it was similar if I heard him right," Pritchard said. "I saw the coverage I wanted and Sherm came through."

Sherm is Richard Sherman, who caught the critical fourth-and-20 pass over the middle before being leveled at the 9 — just past the first-down marker.

First-year Stanford coach Jim Harbaugh said Pritchard called the right play — no surprise considering it worked.

"I knew he'd come through," Harbaugh said of Pritchard, a 6-foot-4, 200-pound sophomore from Tacoma, Wash., who entered the game having thrown three passes. "From the beginning of the week, he had a bounce in his step. He had a gleam in his eye from Sunday on. We have found a true warrior."

The Cardinal (2-4, 1-3 Pac-10) scored 17 points in the fourth quarter and moved 45 yards in 11 plays for the winning touchdown after USC's John David Booty threw the third of his four interceptions. Wopamo Osaisai's 18-yard return gave Stanford the ball with 2:50 remaining.

"It hasn't set in yet," a jubilant Pritchard said. "I'm beside myself — I don't know what to do. Our defense kept us in the game all night. It gave me a chance to get untracked."

Pritchard, filling in for T.C. Ostrander, completed 11 of 30 for 149 yards and the winning TD. The numbers weren't great, but he was awfully good when it counted most.

Ostrander didn't play after suffering a seizure in a restaurant last Sunday. He's OK, but might have trouble getting his job back from Pritchard, a nephew of former Washington State quarterback Jack Thompson.

In the days leading up to the game, Harbaugh stuck to his preseason assessment that USC might be the greatest college football team ever. In the end, the Trojans weren't the best team in the Coliseum.

"Jimmy had them ready to play," USC coach Pete Carroll said. "To give it up like this is a shame, it is crushing to me. Give credit to Stanford. They did a heck of a job and we made a ton of mistakes. We need to find ways to make plays and go back and find the right combinations.

"I never thought we'd lose tonight, even after they scored."

USC might also have to turn to a backup quarterback. Booty cracked the middle finger on his throwing hand when he hit it on a helmet in the second quarter.

"He fought through it and was doing all right," Carroll said. "We could have made a change but we went with our guy. I don't know about next week."

The Trojans (4-1, 2-1) dropped from No. 1 to No. 2 in the AP Top 25 after barely holding on for a 27-24 victory over underdog Washington in Seattle last weekend. They'll drop a lot more this week after losing to a team that had been outscored 141-51 in Pac-10 play.

USC's 35-game winning streak at the Coliseum is over. The Trojans hadn't lost at home since Stanford beat them 21-16 on Sept. 29, 2001, in their first year under Carroll.

The Trojans rolled up 459 yards to just 235 for Stanford. But USC's five turnovers and Pannel Egboh's block of USC kicker David Buehler's PAT attempt early in the game proved decisive.

Booty went 24 of 40 for 364 yards, but in the end, that wasn't enough. Patrick Turner caught nine passes for 83 yards and Fred Davis had five receptions for 152 yards.

"I felt some pressure from their defense during the game, and at the end, had some urgency and forced some things," Booty said.