Seattle (AP) — Southern California's Stafon Johnson stayed face down on the turf. Jubilant Washington players and fans stepped over him, on their way to a riotous purple party that stretched from goal line to goal line.

USC coach Pete Carroll was forced to watch it all, glumly waiting for Steve Sarkisian to emerge from the throng to congratulate his protege. The post-Ohio State funk Carroll began warning his guys about seven days earlier — in the locker room in Columbus, Ohio — leveled the Trojans again.

Jake Locker improvised his Huskies to a steely, 68-yard drive that ended on Erik Folk's 22-yard field goal with 3 seconds remaining, and the Huskies' fired-up defense stymied fill-in quarterback Aaron Corp and No. 3 USC in a 16-13 victory Saturday.

USC has now lost to an unranked team each of the last four seasons.

"Washington wasn't the better team. They just outplayed us," said a shrugging Joe McKnight, who ran for 100 yards on 11 carries with USC's only touchdown. "Clearly, we have superior athletes. But hard work beats athleticism any day."

Carroll's team was stung by eight penalties, an 0-for-10 conversion rate on third down and three turnovers inside the Washington 35.

"We didn't get any better from last week," he said. "I'm not doing a good enough job of making the points of how we win."

One year after Oregon State upset USC in the Pac-10 opener following an impressive Trojans win over Ohio State, an old friend upset Carroll's powerful team. Washington coach Steve Sarkisian was his offensive coordinator before taking over in Seattle in January, trying to rebuild a team that had the Pac-10's first 0-12 season last year.

"It's unbelievable," Sarkisian said. "It's a great moment for our program and hopefully sends a message of where we're headed."

The Trojans are headed back to playing catch-up in the race for a national title.

Quarterback Matt Barkley, who directed an epic game-winning drive to beat the Buckeyes 18-15 in Columbus, Ohio, last week, watched USC's latest stunning upset from the sideline. The 19-year-old freshman was out with a sore shoulder, yielding this week's star status to Locker for one of the most memorable wins in Washington's proud but recently buried history.

The Trojans were also without All-American safety Taylor Mays. He missed his first career game because of the right knee ligament he sprained against the Buckeyes.

"It's a slap in the face," Mays said of the loss in his hometown.

USC (2-1, 0-1), nearly a three-touchdown favorite, was held to its fewest points since a 13-9 loss to UCLA on Dec. 2, 2006, by a defense that allowed Idaho 412 yards last week.

Washington (2-1, 1-0) came in riding a 10-game losing streak in Pac-10 games. It had broken a conference record-tying 15-game overall skid last week. The Huskies lost 56-0 at USC last season, the biggest rout in the 80-game history of the series. Locker missed that blowout with an injury, but was 21 for 35 for 237 yards while absorbing four sacks Saturday.

This is the highest-ranked team beaten by Washington in Seattle since Nov. 14, 1981, also against third-ranked USC. It was the Huskies' first win over the Trojans since 2001, Carroll's first season at USC.

"I can't really describe it," Locker said, his voice hoarse following emotional tears. "It's an amazing feeling to go through what all of us have gone through and to experience what everyone wants to experience when they play college football."

The Trojans were up 10-0 and outgaining Washington 133-15 just 10 minutes into the game. They then began hurting themselves with mistakes, again allowing a team that seemed to be no match for all their blue chip recruits and future NFL draft picks to beat them.

Last season, it was Oregon State. The year before that it was Stanford. The year before that it was UCLA, when USC had a chance to play for the national title.

Corp, a sophomore making his first career start, was 13 for 22 for 110 yards with one interception.

"I felt I was prepared. I just didn't execute," Corp said, solemnly.

Carroll had Barkley warming up behind the bench in the fourth quarter but decided not to use him because the freshman's couldn't get his shoulder loose.

"We didn't throw the ball very well today. It was obvious," Carroll said. "We couldn't get the ball down the field very much. We've rarely been in that situation."

Still, USC was in position to pull it out.

McKnight took off on a 34-yard run — and receiver Ausberry recovered his fumble at the end of the sprint — to get USC to the Huskies 22 while down 13-10 with 6 minutes left. But Donald Butler, who had 12 tackles, one interception and one forced fumble, stopped Johnson on third-and-6. That forced the Trojans to settle for a 25-yard field goal from Jordan Congdon that tied it at 13 with 4 minutes remaining.

USC's offensive players angrily yanked their chin straps off for not taking the lead.

Locker, who came to Washington three seasons ago a much-hyped freshman much like Barkley, made the Trojans pay.

On third-and-15 with 3:03 left, Locker connected with Jermaine Kearse for 21 yards on a rollout play. Locker rolled out for 4 yards to convert another third down to the USC 39 with a minute left.

Locker then avoided a rush, and fired 19 yards to Kearse, to the 16. Locker and Kearse shared a leaping chest bump, old Husky Stadium swayed, and a roughing-the-passer penalty put the Huskies at the 8 with 33 seconds left.

One running play later, Washington called time out with 7 seconds left to put Folk in position. The sophomore from Woodland Hills, Calif., nailed it down the middle.

USC tried multiple laterals on the final play, the kickoff, but couldn't get out of its own end.

After gaining 223 yards in the first half, USC had just 80 in its first three drives after halftime against a defense of which its own coordinator, former Trojans defensive coordinator Nick Holt, said this week: "There are deficiencies there with personnel."

Not this week.