SOUTH BEND, Ind. >> Notre Dame showed the mental toughness against Southern California it was sorely lacking in an embarrassing 35-point loss last season.

The No. 14 Fighting Irish rallied for 17 points in the fourth quarter after blowing a two-touchdown lead, and took the lead on Corey Robinson’s diving catch with 9:06 left in a 41-31 victory Saturday night.

“Our theme all week was the mental toughness that we wanted to exhibit today, it was the one question we wanted to answer,” Notre Dame coach Brian Kelly said. “I didn’t see anything on the sideline that resembled our guys not believing they were going to come back.”

C.J. Prosise ran for 143 yards and two touchdowns, and DeShone Kizer threw two scoring passes, the second the 10-yarder to Robinson that made it 38-31. It was the first touchdown of the season for Robinson, who dropped several passes in the loss at Clemson.

“I just had to step up when my number was called. Thank God I was able to step up for this team and contribute to our success,” Robinson said.

The Irish (6-1) also added a touchdown by former USC player Amir Carlisle on a blocked punt.

Southern California played for the first time since firing coach Steve Sarkisian on Monday. USC coaches are now 0-7 in their first games against Notre Dame in South Bend with Clay Helton, who took over for Sarkisian, becoming the second straight interim coach to fall. Two years ago it was Ed Orgeron following the firing of Lane Kiffin. The Trojans have had four different coaches against the Irish the past four seasons.

“We had great momentum going into the second half. And then, at the end of the day, mistakes hurt us, whether it was penalties, special teams, some missed tackles and some turnovers on offense,” Helton said. “You can’t have those mistakes.”

DeShone Kizer, who was 15 of 24 for 227 yards, said it was a big win for the Irish.

“It’s huge. To come out here and get a signature win like that against USC is big for us and for the season moving forward,” he said.

The victory looked in doubt when the Trojans (3-3) scored three straight touchdowns to take a 31-24 lead as the Trojans scored on a 75-yard catch by JuJu Smith-Schuster and Adoree Jackson scored on an 83-yard pass. But the Irish rallied to win the Jeweled Shillelagh for the third time in four seasons.

“If you miss a tackle, those kids are gone,” Kelly said. “They make you pay dearly, and we missed some tackles.”

It marked the first time in seven tries the Irish beat the Trojans after losing by 30 or more the season before.

Cody Kessler threw two touchdown passes and ran for another score for USC, but the Irish picked him off two passes in the fourth quarter to put the game away.

In a game of shifting momentum, the Irish scored 40 points against the Trojans for the first time since 1977 when Norte Dame warmed up in blue jerseys, then came out in green jerseys and beat USC 49-19 en route to the national championship.

The Trojans lost consecutive games for the first time since losing three straight to end the 2012 season. USC has three losses this early in the season for the first time since starting 1-4 in Pete Carroll’s first year as coach in 2001.

The loss also adds to the mounting troubles the Trojans are facing with a game next week against No. 4 Utah followed by a game at No. 23 California. USC athletic director Pat Haden, who spent 12 years as a color analyst on Notre Dame television broadcasts, was feeling lightheaded just before kickoff and was taken to the locker room. Haden made a stop at the hospital, then headed back to Los Angeles on a private plane.

Haden has been under scrutiny for his hiring of Sarkisian and for allowing Sarkisian to continue to coach after slurring his words and using inappropriate language during an event in August and other struggles by the football team.

“It’s tough when you play a very good football team like that, and these guys have had so much this week and dealt with everything you could possibly think of, and I’m so proud of them,” Kessler said. “They put everything they had into that game. No one gave us a fighting chance and these guys came out and showed they had heart and were competitive, but at the end of the day there were too many mistakes.”