Los Angeles, CA (Sports Network) - Tavita Pritchard's 10-yard touchdown pass to Mark Bradford set up Derek Belch's game-winning PAT with 49 seconds left, as the Stanford Cardinal upended the No. 2 USC Trojans, 24-23, in Pac-10 action at the L.A. Coliseum.

Belch's 26-yard field goal with 5:43 remaining put the Cardinal within reach, 23-17, and their defense got the ball back, as Wopamo Osaisai intercepted a John David Booty pass and returned it 18 yards to the USC 45-yard line.

A pass interference penalty on Kevin Ellison moved Stanford up to the 30-yard line on its final drive, and a four-yard Jeremy Stewart run and a seven-yard Pritchard keeper gave the Cardinal a first down. A holding penalty pulled Stanford back to the 29-yard line, and after a pair of incomplete passes intended for Evan Moore, Pritchard hooked up with Richard Sherman for 20 yards on 4th-and-20.

"It was so loud, I couldn't hear the coach," Pritchard said. "I called my own play, and Sherm (Sherman) came through."

After Pritchard rushed for four yards, he threw two incomplete passes intended for Moore. On 4th-and-goal from the five-yard line, Stanford committed a substitution infraction with 12 men on the field. Nonetheless, Pritchard found Bradford leaping over cornerback Mozique McCurtis in the back left corner of the end zone with 49 seconds on the clock. The extra-point put Stanford ahead, 24-23, as USC prepared for the final drive.

On 1st-and-10 from the USC 41-yard line, Booty got sacked for his career-high fourth time. He next threw an incomplete pass intended for Patrick Turner, and on 3rd-and-17 from the USC 34, Bo McNally intercepted a Booty pass and Stanford ran out the clock to seal the upset.

"This has not set in with me yet," said Pritchard. "Our defense kept us in the game all night. It gave me a chance to get untracked."

USC (4-1, 2-1 Pac-10) came into this contest having won 35 consecutive home games and 24 straight Pac-10 games at home. The last time the Trojans lost a league game at home was to this same Stanford squad in 2001.

"Jimmy (first-year Stanford coach Jim Harbaugh) had them ready to play," USC coach Pete Carroll said. "To give it up like this is a shame, it is crushing to me. We made a ton of mistakes. We need to find ways to make plays and go back and find the right combinations. Give credit to Stanford."

The Trojans had dropped out of the top spot in the FBS standings this week as voters put LSU at the top spot.

Playing in place of injured starter T.C. Ostrander, Pritchard completed 11- of-30 passes for 149 yards with a touchdown and an interception for Stanford (2-4, 1-3 Pac-10), which had dropped back-to-back league tilts to Oregon (55-31) and most recently, Arizona State (41-3). Anthony Kimble rushed for 32 yards on 17 carries with a touchdown, and Bradford caught five balls for 87 yards.

Booty completed 24-of-40 passes for 364 yards with two touchdowns and four interceptions for the Trojans, who prevailed at Washington last weekend, 27-24. Chauncey Washington rushed for 75 yards on 23 carries with a score, and Fred Davis caught five balls for 152 yards and a touchdown.

David Buehler's 34-yard field goal with 6:25 left in the first quarter put USC on the board first. A one-yard touchdown run by Washington midway through the second gave the Trojans a 9-0 halftime lead, as Buehler's PAT attempt got blocked by Pannel Egboh, whose play proved decisive.

USC threatened again on its following possession by marching 51 yards to the Stanford one-yard line, however Nick Sanchez tackled Washington shy of the goal line on 4th-and-goal with eight seconds remaining in the half, after the Trojans elected not to attempt a field goal.

Stanford's defense got the Cardinal going in the second half when Austin Yancy returned an interception 32 yards for a score just more than three minutes into the third quarter.

Nine minutes later, a 63-yard touchdown pass from Booty to Davis capped a six-play drive and increased USC's lead to 16-7 heading into the fourth.

Stanford needed nine plays over three minutes to score on a one-yard touchdown scamper by Kimble, cutting the Cardinal deficit to 16-14 in the opening minute of the final quarter.

But, USC gave itself a 23-14 margin with 11:04 to play as Booty found Ronald Johnson for a 47-yard touchdown pass.