Los Angeles, CA (Sports Network) - Mark Sanchez's 25-yard touchdown pass to Fred Davis early in the fourth quarter provided 10th-ranked Southern California with a 20-13 win over Arizona.

Sanchez came up big when it counted in his first career start, as he replaced an injured John David Booty, who broke the middle finger on his throwing hand in last week's 24-23 home loss to Stanford.

Sanchez completed 19-of-31 passes for 130 yards and was picked off twice for the Trojans (5-1, 3-1 Pac-10), who played without much gusto until a 45-yard punt return by Joe McKnight ignited USC early in the final quarter.

McKnight also rushed for 75 yards and Davis had six receptions for 63 yards for the Trojans, who beat the Wildcats for a sixth straight time.

Willie Tuitama connected on 30-of-43 passes for 233 yards for Arizona (2-5, 1-3), which fell to 3-16 all-time in Los Angeles against the Trojans.

The Trojans held a huge 146-22 yard advantage on the ground.

McKnight's return set up the Trojans at the 25, and on the very next play Sanchez found Davis across the middle in the end zone for a 17-13 USC advantage.

Arizona's Keenyn Crier boomed an 83-yard punt later in the fourth. The kick, combined with a penalty, pinned the Trojans at their one. However, McKnight rumbled 59 yards on a run to move the ball to the Arizona 27. The drive stalled and resulted in a 23-yard field goal from David Buehler with 57 seconds left.

Arizona was unable to move the ball past midfield in the final minute.

Chauncey Washington scored on an 18-yard run in the opening quarter, and Buehler's 27-yard field goal, following an Arizona fumble, midway through the second moved USC to a 10-0 lead.

Arizona responded with 13 consecutive points. Tuitama ran one yard to the end zone with 5:31 left in the half and the Wildcats tied the game with 1:02 remaining on Jason Bondzio's 28-yard field goal to tie the score. The kick came after Sanchez was picked off by Antoine Cason.

Bondzio's 45-yard field goal less than five minutes into the third moved the Wildcats to a 13-10 lead.