Nickell Robey is defensive stopper in Trojans win over Irish

Reporting from South Bend, Ind. -- Defensive back Nickell Robey is only 5 feet 8, but he played a huge role for the Trojans Saturday by neutralizing Michael Floyd, Notre Dame’s star receiver, in a 31-17 USC victory.

Floyd, 6-3 and 224 pounds, managed only four catches for 28 yards. Last season, when the Fighting Irish defeated USC at the Coliseum, he had 11 receptions for 86 yards and a touchdown. He entered the game with 53 catches and averaging 106.5 yards receiving per game.

Robey, a sophomore, broke up a pass to him on the first play of the game and also defended effectively on pass to Floyd in the end zone near the end of the first half.

Then, with 6 minutes 43 seconds left in the game, he sealed USC’s victory when he intercepted a Tommy Rees pass by jumping in front of Floyd on a curl pattern.

Tough running

USC ran for 219 yards, mostly on the legs of two banged-up running backs.

Marc Tyler, who was questionable at the beginning of the week because of a dislocated shoulder sustained in the California game, rushed for 67 yards in 13 carries.

He did so after being held out of contract drills during practice.

His backup, Curtis McNeal, ran for 118 yards in 24 carries, finishing strong even though he sustained an undisclosed injury that resulted in his being helped to the locker room before halftime.

Scoring connections

USC tight end Randall Telfer caught his second touchdown pass of the season to give USC a 7-0 lead.

Telfer also scored against Syracuse on a 44-yard touchdown pass play.

Five of quarterback Matt Barkley’s 19 touchdown passes have gone to tight ends Telfer and Xavier Grimble, both redshirt freshmen.

Eight of the others have gone to wide receiver Robert Woods, who bounced back from a season-low five catches against Cal to pull in 12 receptions for 119 yards and two touchdowns against Notre Dame.

Adding insult

Referee Land Clark, a Pacific 12 Conference official, mistakenly said “Timeout UCLA,” when the Trojans called a timeout in the second quarter.

Earlier this season, a referee called the Trojans South Carolina.

Injury report

Kicker Andre Heidari, who had just kicked a 25-yard field goal in the second quarter, suffered an undisclosed injury on the next play — George Atkinson III’s 96-yard kickoff return for a Notre Dame touchdown.

Walk-on Craig McMahon took his place at the start of the second half but Heidari returned from the locker room early in the third quarter.

However, when USC was faced with fourth down at the Notre Dame 30 on its first possession of the second half, the Trojans chose to punt instead of trying a 47-yard field goal. A short time later, it became clear why: Heidari missed badly from 32 yards out.

Heidari looked better on a point after later, finishing four for four on conversion kicks.

Into the future

The Notre Dame sideline was packed with high school players in for an official recruiting visit, including lineman Arik Armstead, who withdrew his commitment to USC last week.

The group also included Gunner Kiel, a 6-foot-4, 220-pound quarterback who de-committed from Indiana and is reportedly considering Notre Dame and USC, among others. Kiel is the nephew of former Notre Dame quarterback Blair Kiel.

gary.klein@latimes.com twitter.com/latimesklein Staff writer Mike Hiserman contributed to this report from Los Angeles.