Reggie Bush rushed for 160 yards and three touchdowns for the Trojans (6-0), who extended the nation's longest winning streak to 28 games. Dwayne Jarrett added four catches for 101 yards, including a 61-yard reception on fourth down to keep the final drive alive.
Leinart went 17-of-32 passing for 301 yards and two interceptions. The reigning Heisman Trophy winner, who threw no scoring passes, was able to guide the Trojans on a 75-yard, nine-play game-winning drive.
Brady Quinn, who gave the Fighting Irish a 31-28 lead with a five-yard touchdown run just before the game-winning score, was 19-of-35 for 264 yards, one touchdown and one interception.
Jeff Samardzija had six catches for 99 yards and one touchdown for Notre Dame.