USC and Notre Dame will meet on Saturday to write another chapter in their rivalry, one that is widely regarded as one of the greatest in all of college football. The Notre Dame Fighting Irish have defied all expectations and have risen to the No. 1 spot in the polls, while the USC Trojans have defied all logic and have plummeted from the rankings entirely.

The contest between these two schools is often competitive, and this year proves to be no different. The Trojans want desperately to upset the top dogs to prove they weren’t all hype and no prep, while the Irish want National Championship glory, something they haven’t achieved since Ronald Reagan was in office.

The Trojans were supposed to be the team to beat, but four losses later, it looks as if this team could not handle the pressure and as such, it has greatly underachieved. Matt Barkley has regressed a lot this season—throwing more picks this year than he did as a freshman—and will be missing this game entirely, as he suffered a separated shoulder at the hands of cross-town rivals UCLA.

Notre Dame, on the other hand, has been playing like a championship team, led by tremendous efforts from QB Everett Golson and Trojans-commit-turned-Irish-star LB Manti Te’o.

To better understand this match up, we spoke to Keith Arnold of NBC Sports. He sheds light onto just how deep this Notre Dame is, and how the Irish can avoid a blunder in the final game of their undefeated season.

1. Notre Dame has surpassed everyone's expectations this year, going undefeated coming into Saturday's clash with their rivals, USC. What has changed with Brian Kelly's team from 2011 to 2012?

Arnold: Between the lines, they stopped turning the ball over. As USC fans probably understand, you can have all the talent in the world on offense, but if you're turning the ball over a lot, you're just not going to win many games. On top of the turnovers, the defense continued to progress in Kelly's third season. Manti Te'o got healthy after an ankle injury nagged him all season and the defensive front has been among the best in college football.

Offensively, the Irish turned themselves into a more physical running attack, while Everett Golson learned on the job. Tyler Eifert hasn't put up numbers like he did last season, but he's probably the top tight end in college football. And as Golson has progressed, his strong arm, accuracy, and ability to run has added another element to the offense.

Lastly, this football team is just tougher mentally. A third season in Kelly's system has flushed any remnants of mediocrity from the program and it's helped develop a football team that's very difficult to beat.

2. With Max Wittek playing in place of Matt Barkley, Notre Dame has no film on him. Does going into this game with no practical knowledge of his skills pose as an issue for the Fighting Irish?

Arnold: I don't think so. Notre Dame will prepare for Wittek the same way they prepared for Barkley. The only difference being Barkley is among the best to ever to play quarterback for the Trojans and Wittek is making his first start ever. Notre Dame recruited Max Wittek and they know the skill set he possesses.

And while Lane Kiffin has raved about the work Wittek's done this week, the most likely scenario for a redshirt freshman making his first start against one of the country's best defenses isn't usually kind. If Wittek can keep the Trojans in the game, keep the turnovers to a minimum, and manage the offense, that's about the best scenario USC could ask for.

3. Notre Dame and USC have a deep rivalry. What elements of this game will make this matchup one for the ages?

Arnold: The only element that makes this a match-up for the ages is the fact that USC can play spoiler to one of Notre Dame's most surprising seasons in a quarter-century. In a game that is a role-reversal from the one many expected, if a redshirt freshman back-up quarterback could end the Irish's dream run, that will be a story that could go down in USC lore for a long time, adding a thorn in the side of Irish fans everywhere.

Another story to watch is that of Manti Te'o. After Notre Dame all but christened Heisman runs for Carson Palmer and Matt Leinart, a big game on Saturday night for Te'o could springboard him to the top of the Heisman race, giving the linebacker a historic win.

4. We know that Everett Golson and Manti Te'o are the real deal, but aside from them, this Notre Dame squad is not perceived by Trojans fans to be that deep. Who are some other real factors that USC should get familiar with?

Arnold: Trojans fans might be underestimating this group, then. On offense, the Irish have tight end Tyler Eifert, a returning consensus All-American and a guy that'll probably go in the first round. At running back, Cierre Wood is averaging more than seven yards a carry and along the offensive line, left tackle Zack Martin hasn't given up a sack since the season opener in Dublin. TJ Jones and Robby Toma won't garner much attention, but have been rock solid all year.

Along the defensive line, Stephon Tuitt and Louis Nix are among the nation's best. Tuitt has twelve sacks and is a 6-foot-6, 300-pound monster that's only a true sophomore. Nix is among the most disruptive nose guards in the country and will have a great match-up with Khaled Holmes. Outside of Te'o, the Irish linebacking corps is playing great football, with Prince Shembo a very dangerous pass rusher coming off the edge. At safety, Zeke Motta holds down the secondary and will likely work his way into the middle rounds of the NFL Draft.

5. What are USC's strengths that could help them pull off an upset of the No. 1 Fighting Irish?

Arnold: The same traits that had the Trojans ranked No. 1 in the country. There's an insane amount of talent on this football team and Notre Dame knows that. They just haven't been able to get out of their own way this season, and really haven't had a win against an impressive team all season.

6. Notre Dame's secondary hasn't seen many teams with elite WR talent like USC has. Is going up Marqise Lee, Robert Woods and Nelson Agholor something that could spell trouble for this team?

Arnold: I think we all know that answer is yes. That trio would be better than a lot of NFL teams. But the Irish have done a great job in the secondary this year with a rebuilt unit, and they've gotten a ton of help from Notre Dame's excellent pass rush, a defensive line that's gotten pressure while only needing to bring three or four rushers.

The key to the game for the Irish will be tackling. They'll be happy giving up the underneath throws. But then they've got to tackle Lee, Woods, and Agholor, no easy feat.

7. As a whole, how can Notre Dame slow down USC's offense if it is moving on all cylinders?

Arnold: Keep the ball out of their hands. Brian Kelly has been very good at minimizing possessions for opponents and playing rock solid red zone defense. If the Irish can control field position, put the Trojans on a long field, and then plain keep the ball out of USC's hands, they'll be playing to their strengths. This is where having Wittek in the game really could hurt USC, as they'll need to be efficient on offense and score when they have their chances, as Notre Dame should control the clock with their running game.

Thanks to Keith Arnold for helping us preview Saturday's game. Follow him on Twitter, @KeithArnoldNBC.

Reach staff writer Trenise Ferreira here. Follow her on Twitter, @TreniseF_RoT.