Highly touted freshman Joe McKnight gave the Trojans the big plays they desperately needed, Mark Sanchez threw his first career touchdown pass, and No. 10 USC rallied to beat Arizona 20-13 today.

Sanchez, a third-year sophomore making his first start, threw a 25-yard scoring pass to Fred Davis with 10:47 remaining on the first play after McKnight electrified the Los Angeles Coliseum crowd of 84,671 with a 45-yard punt return.

Suddenly, the Trojans led 17-13, and their defense held the Wildcats without a first down after that. David Buehler kicked a 23-yard field goal with 57 seconds left to complete the scoring.

The game was USC's first since a shocking 24-23 loss to 41-point underdog Stanford, snapping the Trojans' 35-game homefield winning streak. It appeared they were going to go down again, this time as 21-point favorites, before McKnight's first big play. A punt hadn't been returned for more than 12 yards against Arizona punter Keenyn Crier previously this season.

Crier's 83-yard punt — one yard shy of the school record set in 1930 — rolled dead at the Trojans' 1 with 7:09 remaining. But after USC picked up a first down, McKnight raced 59 yards to the Arizona 27.

Sanchez later scrambled for 10 yards to the Arizona 2 on a third-and-7 play, and Buehler kicked his second field goal of the game three plays later.

USC (5-1, 3-1 Pac-10) won despite being held to 12 total yards in the second quarter and 50 in the third period.

The Wildcats (2-5, 1-3) were clearly the better team until McKnight's punt return, overcoming a 10-0 deficit.

Sanchez, who entered having thrown 10 college passes, completed 19 of 31 for 130 yards with two interceptions. He was filling in for John David Booty, who broke the middle finger on his throwing hand against Stanford.

McKnight finished with a career-best 75 yards on 13 carries. He returned two punts for 15 yards and rushed for 79 yards on 16 carries in his first five games at for the Trojans.

Arizona's Willie Tuitama completed 30 of 43 for 233 yards. The Wildcats were held to 22 yards rushing.

Jason Bondzio kicked a career-long 45-yard field goal early in the third quarter, giving the Wildcats their 13-10 lead. Neither team would threaten to score again until McKnight's punt return.

The Trojans moved 85 yards on 10 plays the second time they had the ball, scoring on an 18-yard run by Chauncey Washington for a 7-0 lead.

Tuitama completed 10 passes for 67 yards before throwing his first incompletion late in the first quarter, but the Wildcats lost a fumble and punted twice in the period.

Sedrick Ellis recovered Nic Grigsby's fumble at the Arizona 31 early in the second period, setting up a 27-yard field goal by Buehler to make it 10-0.

The rest of the quarter belonged to Arizona.

First, the Wildcats moved 74 yards on eight plays, scoring on a 1-yard run sneak by Tuitama, who completed 4-of-4 passes for 67 yards on the drive.

Then, three plays after Antoine Cason's 13th career interception and 27-yard return to the USC 19, Bondzio kicked a 28-yard field goal to make it 10-all.

Corey Hall intercepted another pass by Sanchez following the kickoff, but fumbled at the end of a 17-yard return and Matt Spanos recovered.