Linebackers Chris Galippo and Devon Kennard came up big for the Trojans on Saturday night in a 20-16 loss against Notre Dame at the Coliseum.
Galippo, who suffered a concussion last week against Oregon State, was animatedly calling out signals and directing teammates moments before leaping to intercept a first-quarter pass by Fighting Irish quarterback Tommy Rees.
The play helped set up USC's only first-half points, a 45-yard field goal by Joe Houston with 4 minutes 9 seconds left in the first quarter.
On the first possession of the second half, Kennard tipped a Rees pass into the air and then grabbed it and returned the ball eight yards to the Irish 21-yard line.
The play set up Houston's 23-yard field goal that cut Notre Dame's lead to 13-6.
Galippo also forced a fumble that nearly thwarted Notre Dame's game-winning drive in the fourth quarter, but the Fighting Irish managed to recover.
Houston's 45-yard kick was the longest of his career and he later added field goals from 23 and 37 yards to improve to 10 of 16 this season.
The 45-yard field goal was the longest by a USC player since David Buehler converted from 46 yards out against UCLA in 2007.
USC Coach Lane Kiffin had talked of making a game-time decision regarding quarterback Matt Barkley's status, but Barkley was not on the field for initial warmups.
The sophomore, who suffered a high ankle sprain against Oregon State, came out onto the field after seniors were introduced to the crowd.
Barkley, a team captain, went to midfield for the coin toss but did not play.
Fullback Stanley Havili and quarterback Mitch Mustain got the loudest ovations during the senior introductions.
Sophomore safety T.J. McDonald, the Trojans' leading tackler, suffered a shoulder injury in the first half and did not return.
McDonald was replaced by walk-on Tony Burnett.
Baxter comes back
Freshman tailback Dillon Baxter returned to action after being reinstated by the NCAA earlier in the week.
Baxter had been ruled ineligible before the Oregon State game because he accepted a ride on a golf cart from a USC student who is also an agent. The ride is considered a prohibited extra benefit.
Baxter had one carry for four yards and threw one pass for a gain of four yards.
Smith sits, Lewis starts
Offensive tackle Tyron Smith had played the last few weeks on two sprained ankles, but he was not in the lineup against Notre Dame after suffering a knee injury against Oregon State.
Butch Lewis started in Smith's place.
Lewis began the season as the starting left guard but lost his job to Michael Reardon.