Notre Dame and USC enter Saturday night's game at Los Angeles Memorial Coliseum on different two completely different paths from when the season started.
The Irish (11-0) went from not being ranked in the preseason to the No. 1 team in the BCS standings along with the Associated Press Top 25 and USA today coaches polls and win away from playing for a national title.
The Trojans went from preseason No. 1 to unranked and hoping to play spoiler to the Irish.
"That's why they play the games," coach Brian Kelly said during his Tuesday news conference. "There's so many factors that go into this. We know the unexpected is always out there."
The unexpected for Notre Dame when it kicks off against USC at 8 p.m. Saturday in a game televised by ABC is Trojans quarterback Max Wittek.
The 6-foot-4, 235-pound freshman will make his first start for the Trojans against the Irish because USC star quarterback Matt Barkley injured his shoulder in last weekend's loss to UCLA.
There is not a lot known about Wittek, but he has completed 8 of 9 passes for 95 yards with a touchdown. And as Kelly puts it, Wittek was good enough to get a scholarship at USC.
"When you get a scholarship to USC, you're one of the best quarterbacks in the country," Kelly said. "He's a big, strong, physical kid. He's got a live arm. He certainly fits into their offensive scheme of things. He's a perfect fit for what they do."
Wittek connected on all three of his pass attempts and finsihed with 40 passing yards against UCLA when he replaced the injured Barkley.
Even though Wittek has limited expereince, Kelly said he doesn't plan on making changes to his defense to disrupt the USC freshman.
"We're going to do what we do," Kelly said. "At this point, for us to go into one game and say, all right, we're going to do different things to confuse Max is really crazy.
"This guy has watched football all year, he's going to be watching film, he knows our defense. We're going to do what we do, because that's gotten us to that point. No big changes on our end."