LOS ANGELES -- Ronald Johnson settled under the pass at the Notre Dame 15 with no defenders anywhere near him. Southern California was almost certain to beat the Irish yet again when he made an easy touchdown catch in the waning seconds of his final home game.

Only he didn't.

"It was about time we caught a break," Notre Dame coach Brian Kelly said.

And he wasn't just talking about a dropped football that will bounce around for years in the lore of college football's best intersectional rivalry.

Robert Hughes scored on a 5-yard run with 2:23 to play, and Notre Dame rallied to snap an eight-game losing streak against the Trojans with a 20-16 victory Saturday night.

Freshman quarterback Tommy Rees overcame four turnovers to lead bowl-bound Notre Dame's 77-yard go-ahead drive, but the teenager and his teammates never breathed easily on a cold, rainy night in Los Angeles -- not even after Johnson's horrific drop with 1:17 to play.

After the tragic death of a student videographer during practice last month, after several tough losses for a program with expectations usually dwarfed by reality for the past two decades, Kelly and his players reveled in a celebration in the Coliseum locker room after reclaiming the Jeweled Shillelagh -- even if they needed an incredible blunder to get it.

"We knew that if a talented receiver like that was going to drop a ball like that in a situation like that, it's definitely our night," Notre Dame linebacker Manti Te'o said. "Things like that don't happen without a reason. It's a huge night for this program and in our lives."

Mitch Mustain, making his first USC start in place of injured Matt Barkley, still converted on fourth down after the drop, and moved the Trojans to the Irish 23.

Notre Dame (7-5) clinched its third straight victory when safety Harrison Smith leaped for an interception on a poor throw at the goal line with 36 seconds left.

"We brought the fight back in the Fighting Irish," Kelly said.

Johnson will remember his mistake on Senior Night for the rest of his life. The normally sure-handed senior held his hands to his helmet in disbelief after bobbling away a sure TD pass in the final minutes of his final home game at USC (7-5).

"It's part of the game. You drop balls," said Mustain, who passed for 177 yards. "That one probably would have changed the outcome. I don't know if there's a worse feeling than that."

Neither team was ranked heading into the game for just the ninth time, but Kelly became the first Notre Dame coach to beat USC in his first try since Lou Holtz in 1986. USC's Lane Kiffin also made his rivalry debut -- the first time two rookie head coaches faced off in the game since 1941.

"It's just a shame, because now you've got a whole locker room and the whole Trojan Family all down in the tank at one play [that] could completely change the whole outcome," Kiffin said.

USC's streaks of 19 straight nonconference victories and 15 straight at home ended in the 82nd edition of a rivalry dating to 1926.

Rees passed for 149 yards in his third career start, making huge mistakes but also throwing touchdown passes to Michael Floyd and Duval Kamara. Floyd had 11 catches for 86 yards on his 21st birthday for the Irish.

"I feel a little more down than I normally do after a win," said Rees, who has won starts in South Bend, Yankee Stadium and the Coliseum. "I've just got to do a better job."

The Champs Sports Bowl in Orlando is expected to be the Irish's postseason destination, but the Las Vegas Bowl also showed up to scout Notre Dame.

USC's conservative offense scored all of its points off Rees' turnovers, and Joe Houston kicked his third field goal with 6:25 to play after another short drive set up by Rees' third interception. But the Notre Dame finally kicked into gear, with tailbacks Cierre Wood and Hughes making big runs before Hughes scored on a charge straight up the middle.

Mustain was once among the nation's top high school quarterbacks, but he hadn't started a game since his freshman season as Arkansas in 2006, when he went 8-0 for the Razorbacks. After transferring in the wake of coaching turmoil, he spent the last three seasons backing up Mark Sanchez and Barkley, who sprained his ankle in last week's loss at Oregon State.

Notre Dame took a 13-3 lead into halftime with two late touchdown passes by Rees, but USC hung in with big plays from its defense. Mustain's tying 1-yard TD sneak in the third quarter was preceded by Rees' fumble forced by USC's Nick Perry, who returned it to the Notre Dame 2.

Notre Dame's defense finally gave up a touchdown after 13 straight quarters without allowing one, its longest such stretch since 1980.

Marshall Jones then picked off Rees' throw at the Notre Dame 38, and Houston made a 37-yard field goal to put the Trojans ahead.