Marquee Matchup (1) USC at (14) Nebraska 8:13 p.m. ET, ABC Memorial Stadium (capacity 85,197) Lincoln, Neb.

Breaking down the weekend's biggest game, as USC tries to hold on to No. 1.

Three things you should care about

1. Sam Keller is 23 months older, supposedly wiser and more prepared than he was when he threw five interceptions against USC as Arizona State's quarterback in 2005. He's even wearing that white arm sleeve as a symbolic gesture to hide his ink. But really, how much different of a QB can he be?

That debacle against the Trojans was Keller's last big-game experience. In said game, Keller's Sun Devils led 21-3 at halftime and the QB prematurely pumped his fist toward the student section, only to implode in the second half. While he's looked better in Weeks 1 and 2, Keller has still shown a dangerous tendency to force passes into coverage. And USC's front seven -- especially feared end Lawrence Jackson -- is going to apply far more heat on the pocket than Nevada or Wake Forest did. Said one assistant coach who has faced the Huskers this year (and breaks down Marlon Lucky later), "It's a different game when you put pressure on Keller. You'll have some opportunities for turnovers."

Keller is wise enough not to throw five picks this time around. Nebraska isn't going to beat USC by playing ultra-conservative football, though. He'll have to take his share of shots downfield, and inevitably, a few will get him into trouble.

2. USC won't break the game open unless it gets a big day from either Patrick Turner or David Ausberry.

Last season in L.A., Nebraska was scorched by giant Trojans wideout Dwayne Jarrett, who racked up 136 receiving yards and scored two touchdowns on 11 catches. Perhaps the biggest difference from the '06 game to this one, aside from the Huskers' new quarterback, is that USC's receiving corps got greener while Nebraska's secondary got immensely better. Neither Ausberry nor Vidal Hazelton was required to do much against Idaho in Week 1, and Turner, a 6-foot-4 sophomore who has the most experience, sat out as a precaution after suffering a neck injury in practice.

The Huskers, meanwhile, have welcomed back top cornerback Zackary Bowman, who had to miss last season with a knee injury. The Huskers' 20-17 win over Wake was sealed with a Bowman interception, and there's enough talent around him in the secondary to match up with the Trojans. Forcing USC into a battle of ground games is a feasible way for the Huskers to pull off the upset.

3. The Trojans have the advantage of surprise.

Heisman candidate John David Booty is no mystery to Nebraska defensive coordinator Kevin Cosgrove. There's a whole season of tape available on the USC quarterback, including last year's Trojans-Huskers meeting. The great unknown is how USC's offense actually works in '08. It seemed as if the Trojans revealed less than half of their playbook in a ho-hum, 38-10 win over Idaho. And in that game, which was followed by a bye week, neither their No. 1 wideout (Turner) nor apparent No. 1 running back (Chauncey Washington) played. Makes it tough to get a feel for the offense, no?

Nebraska did not have the luxury of being so buttoned-up. While the Huskers ran he ball down Nevada's throat in Week 1 (Lucky had 233 yards), they were forced to show much more in a narrow win over a solid Wake Forest team in Week 2. Keller threw the ball 41 times, and the game remained undecided until Bowman's interception.

Inside the scouting report

"Lucky is a relentless runner -- he's strong, deceptively fast and relentless. But Nebraska really uses a collective effort to wear you down; it's that big offensive line, with great tackles and a solid center, just controlling the ball. It's not the first quarter that kills you; it just builds, from the second to the third to the fourth, sort of like a heavyweight fight. There's only so many body blows you can take.

YOUTUBING THE BIG SHOWDOWN 1. High-Tech Nebraska Husker fans care as much about their blenders as they do about their football. 2. The Legend of Chuck Barry Wonder why USC players are so well-conditioned? 3. Booty, Peyton Practicing Together It's like Caine and Hackman in the same film! - L.W.

"In terms of running style, Lucky has great cutback ability, and he's also a little bit mean when he finishes runs. Whereas some backs will try to shake you a little bit, it seems like he's set on taking the game right at you.

"When you watch Nebraska, sometimes it'll seem like Lucky is running through great big holes; what they're actually doing is constantly adding gaps with their tight ends and wings. I don't know how many tight ends they have, but it seems like there are constantly more and more of them coming in, and they're shifting and moving and changing the gaps in the running game. Callahan is ingenious in the way that he uses shifting; it's masterful how he can isolate defenders by changing formations.

"I think a veteran defense like USC has -- with all that speed -- could match up very well with him, though. You have to stay as simple as you can. Be gapped out. Load the box and put them in situations where Keller has to pass. It's a different game when you put pressure on Keller; you'll have some opportunities for turnovers. You can't let them get to a point, with a lead, when they say, 'The hell with passing; we're not going to mess around, and just keep coming right at you on every down.' "

The pick

USC 24, Nebraska 20. Booty won't light up the Husker secondary like he did in '06, but the Trojans will grind out enough points to outlast a 100-plus-yard day from Lucky. Keller will be picked twice, including a heartbreaker on the Huskers' final drive.