It's the game all Notre Dame fans have been waiting for since the Fighting Irish disposed of Oklahoma four weeks ago.
Yes, the team needed some help to get to No. 1—including a major collapse by Pittsburgh in a triple-overtime thriller—but it's finally USC week.
The Irish are just a win over the Trojans away from playing for their first national title since 1988.
Notre Dame caught a major break when USC quarterback Matt Barkley was ruled out of the game after suffering a shoulder injury late in last week's loss at UCLA.
The defeat at the hands of USC's crosstown rival knocked the preseason No. 1 team out of the Top 25 after three losses in four weeks.
Despite the Trojans' recent struggles, they are still a dangerous final foe for the Irish to conquer.
Let's look at five keys for Notre Dame on Saturday night at the fabled Los Angeles Coliseum.