The momentum had briefly shifted in Notre Dame’s favor.

The Fighting Irish had marched 71 yards down the field on their first possession of the second half to the USC 1-yard line almost seamlessly, on the verge of tying the game at 17.

Momentum swing · Junior safety Jawanza Starling recovered a fumble from quarterback Dayne Crist at the Notre Dame 1-yard line in the third quarter, scoring a touchdown to give the Trojans a 24-10 lead. - Carlo Acenas | Daily Trojan

But quarterback Dayne Crist, who had replaced starting signal caller Tommy Rees six plays earlier, fumbled the snap and junior safety Jawanza Starling scooped up the ball for an 80-yard touchdown to give the Trojans (6-1, 3-1) a 24-10 lead they would never relinquish en route to a 31-17 victory.

“Everything just slowed down,” Starling said. “I told myself I had to get it. I had to wait for the perfect bounce and not go for it too soon and miss it. That was a big momentum swing. To get a big play like that on defense changed the whole momentum.”

Though the play of the defense had been criticized, especially against Arizona State and Arizona, the Trojans held the Irish to just 267 yards of offense and just seven points in the second half.

Starling, who finished with four tackles, a fumble recovery and a touchdown, noticed the team’s different play.

“[It was] our mindset,” Starling said. “We were more focused [and] determined to shut up everybody who criticized the defense.”

The defense did its part in limiting the Irish, especially in the second half. Senior linebacker Chris Galippo recovered a botched lateral pass and sophomore cornerback Nickell Robey picked off Rees midway through the fourth quarter to essentially put the game away.

Robey also had the assignment of slowing down wide receiver Michael Floyd, the Irish’s top receiver, and limited him to just four receptions and 28 receiving yards.

“He was one of the main targets for us in stopping the passing game,” Robey said. “Coach trusted me enough to go at him one-on-one and that’s what I did. He’s a great player and I tip my hat off to him, but we did a great job of containing him.”

The Trojans also held Rees to just 190 passing yards and one interception. The running game for Notre Dame was also neutralized. Coming into the game, Notre Dame had been averaging 194 yards per contest, but the Trojans limited the Irish to just 41 yards on the ground and an average of 2.9 yards per carry.

USC’s defense might have been the highlight of the night, but it was the USC offense that got it going in the first quarter.

On USC’s first two offensive drives, senior tailback Marc Tyler carried eight times for 54 yards. The Trojans combined for 60 yards on 11 rushes in the half, and USC running backs coach Kennedy Polamalu noted the significance of establishing the running game early, especially on the road.

“It was important,” Polamalau said. “You have to take the physical part to them and we did that tonight. There are some things we need to get better at but tonight from my view, these young men played with their heart and passion and that’s all you can ask for.”

Junior tailback Curtis McNeal finished with 24 carries for 118 yards while Tyler finished with 13 carries for 67 yards. Tyler, who dislocated his left shoulder last week against California, started the game but had to leave because of an apparent leg injury in the second half.

McNeal suffered from cramps in the second half and had to leave for a short period of time. Polamalu was quick to praise USC’s two leading rushers.

“Those two are doing things right,” Polamalu said. “Their football IQ is off the charts, their toughness is off the charts. I’m not just talking about their physical toughness, but their mental toughness.”

USC’s passing game was also on target. Though Barkley and Woods struggled against California last week, the two bounced back in leading the Trojans’ offense.

Woods notched 12 receptions for 119 yards and two touchdowns while Barkley finished 24-of-35 for 224 yards and three touchdowns. USC coach Lane Kiffin praised the signal caller for his performance.

“Even though his numbers are not gigantic, if you don’t get sacked and you don’t turn the ball over with any fumbles or interceptions, you’re going to give us a good chance to win, and he did that,” Kiffin said.

And despite all the attention stemming from this historic rivalry, Barkley expressed the team’s focus throughout the week leading to the big game.

“With all the hype in games like this, it can be easy to stray away from who we are as a team,” Barkley said. “Our guys on offense and defense did a great job just focusing on us. Now we can soak in all this energy from this win and realize what we just did with this rivalry.”

USC returns to the Los Angeles Memorial Coliseum to face Heisman candidate quarterback Andrew Luck and No. 4 Stanford next weekend.