It delivered by holding an opponent in single digits for the first time since November 2009 and forcing five takeaways.
"We needed that," USC head coach Lane Kiffin said Thursday night at AT&T Park. "It was much more important for this team to win like that and to have a game like that for confidence after all the things the defense has been hearing about them – staff, players, everybody involved."
"We had to come out and show everybody that we're not as bad a defense as everyone thinks we are," linebacker Dion Bailey, who intercepted two passes, said after the 30-9 win.
"Hopefully next week we are all firing on all cylinders and we're going to be dangerous."
That energy hasn't yet carried all the way to Sound Bend, Ind. just yet, but was obvious to assistant head coach Monte Kiffin as the Trojans went through a rare Sunday practice to prepare for Notre Dame.
"You can feel it in practice today," the elder Kiffin said. "I think they got some confidence back. They did play well. We did the things you're supposed to on defense.
"You can't always get five turnovers, but every once in a while you're going to have that breakout game."
USC will need to create takeaways against an Irish offense averaging 32.3 points and 467.5 yards of total offense per game.
Notre Dame threw five interceptions and lost five fumbles in losses to South Florida and Michigan.
Given the number of injuries USC suffered coming out of the Weekender, maybe it would have been easier for Kiffin to list the players that are completely healthy this week.
Running back Marc Tyler (shoulder), wide receiver Marqise Lee (shoulder), guard Marcus Martin (undisclosed), cornerback Torin Harris (shoulder), and safety Demetrius Wright (leg contusion) did not practice Sunday.
Tyler was in a sling, but Kiffin and running backs coach Kennedy Polamalu held out hope he would be able to play eight days after the redshirt senior dislocated his shoulder.
"Marc is still our starter until he is called out," Polamalu said.
"We'll see," Kiffin said. "We'll take it one day at a time."
Polamalu, a former USC fullback, said he couldn't recall a running back recovering from that sort of injury in such a short timeframe, but he would have found a way to play.
"Heck, if it was me, I'm stupid, I'd shoot it and play," he said. "They're not me. I want them to be smart. We're part parent and part coach, you want to make sure he's healthy and everything is right.
"I know he's a tough kid. He'll do whatever he can to move back and help the team win."
Redshirt junior Curtis McNeal, who rushed for 86 yards and a touchdown against Cal in relief of Tyler, would likely start if he cannot play.
There was some good news, as linebacker Lamar Dawson saw his most extensive action since spraining his ankle against Syracuse.
-Corner Anthony Brown, who broke his left ankle against Cal and will miss the rest of the season, underwent surgery Friday after returning to Los Angeles.
Kiffin said he expected Brown would be available for spring practice.