LOS ANGELES (AP) -- Todd Husak threw for two touchdowns and ran for the go-ahead score Saturday as Stanford continued its surprising run atop the Pac-10 standings with a wild 35-31 victory over Southern California.

In a game that featured 1,043 yards of combined offense, the Cardinal (5-2, 5-0) finally sealed the victory when safety Tim Smith intercepted a pass by Mike Van Raaphorst at the Stanford 7 as time ran out.

That game-saving interception also made moot a decision by Stanford coach Tyrone Willingham to go for it on fourth-and-1 at the Cardinal 45 with 2:08 remaining after his punter had been inconsistent.

Husak was stopped cold on a quarterback sneak and USC took over for one final chance against Stanford's league-worst defense.

Van Raaphorst threw for a school-record 415 yards, completing 25-of-51 for three TDs with three interceptions. Husak was 20-of-32 for 290 yards with three interceptions.

Brian Allen ran for 121 yards on 15 carries for the Cardinal. The Trojans' Chad Morton had 151 yards on 22 carries as USC (3-4, 1-3) rolled up 587 yards of offense.

The Cardinal came back from an early 21-point deficit as USC blew a second-half lead for the fourth time this year.

Stanford is off to its best start in the Pac-10 since 1970, when the team won its first six league games and went on to the conference title and a Rose Bowl win over Ohio State.

Husak's 1-yard run early in the fourth quarter turned out to be the final score of what had been a freewheeling game.

Stanford reeled off three consecutive touchdowns in a spree that began just before halftime and continued in the early moments of the third quarter to give the Cardinal its first lead, 28-24, with 12:49 left in the third.

USC, which had only a field goal since scoring three touchdowns in the opening quarter, finally got into the end zone again with 6:34 left in the third quarter. Van Raaphorst hooked up with R. Jay Soward on a 64-yard pass play to put the Trojans back in front, 31-28.

Allen broke loose up the middle on a 68-yard run, down to the USC 11, to start the Cardinal on its comeback. Coy Wire bulled into the end zone from the 2 early in the second quarter to cut the Trojans' lead to 21-7.

After the teams exchanged missed field goals later in the quarter, David Newbury hit a 31-yard field goal to put USC up 24-7. But Husak, starting with 56 seconds left in the half, quickly moved the Cardinal down the field, throwing a 23-yard TD pass to DeRonnie Pitts to end an 80-yard drive that took just 30 seconds off the clock.

Stanford's two quick scores in the third quarter came on a 16-yard pass from Husak to Dave Davis and Chris Johnson's 30-yard interception return.

USC was virtually unstoppable the first three times it had the ball. The Trojans chewed up yards and scored on Chad Morton's 1-yard run to cap an 85-yard march. They later scored on an 8-yard pass from Van Raaphorst to Windrell Hayes after a 63-yard drive and on a pass play from Van Raaphorst to Marcell Allmond that covered 64 yards.

With the game just 12:10 old, Stanford already was down by three touchdowns and had given up 230 yards.