LOS ANGELES -- It is quite possible that the USC defense is not the best to come into your living room since Miami in 2001, or Alabama in 1992, or Oklahoma in 1986, or even Penn State in 1947 (a team that, as hard as it is to believe, Joe Paterno did not coach; he played for Brown that season).
Trojans head coach Pete Carroll, for one, is a skeptic about any best-ever claim.
"I think that's easy to talk about and really hard to prove," Carroll said.
Given that the Trojans played a few offenses that would have a hard time moving the ball in a seven-on-seven drill, skepticism has a place in the debate. But so does wonder. Plenty of other teams have played their share of feeble offenses and not achieved the level of dominance that the No. 5 Trojans have enjoyed on defense.
The Trojans shut out three opponents. Five others went scoreless in the second half, including Oregon, which averaged 41.9 points per game. The Ducks lost to the Trojans 44-10.
Notre Dame did not make a first down -- a first down! -- until the final play of the third quarter.
The dominance became so commonplace that the defenders had to remind themselves to focus. All-American free safety Taylor Mays said Sunday that he would envision getting beat deep. "If I gave up that play," Mays said, "it would mess up my whole week."
Linebacker Brian Cushing said Sunday that the defense adjusted its goal from keeping a team scoreless to preventing it from crossing midfield. The Trojans did that, too, in a 69-0 defeat of Washington State. After that, they upped their goal to not letting an opponent get off its bus.
OK, maybe not, but how else to maintain interest?
"I think we got to a point where we didn't really care who we played," Mays said. "We would play anybody, anytime. We would be successful if we executed. We'd have played the Dallas Cowboys if it came to it. That's the confidence we have."
No. 8 Penn State has moved the ball almost at will this season. But the Nittany Lions' offensive coaches understand that razzle and dazzle will take the day off Thursday at the Rose Bowl Game Presented by Citi (ABC, 4:30 ET). If Penn State is to gain yards and score points against USC, the Nittany Lions will have to do so with patience and competence.
"There are times when somebody looks like they are going to break a big play, where it looks like a 30-yard gain, and it becomes second-and-1," Penn State quarterback coach Jay Paterno said. "If they make a mistake, they have so much makeup speed that you're not going to get big plays."
One of the characteristics of the Nittany Lions' only loss, 24-23 at Iowa, is the lack of big plays. Penn State had one gain of 20 yards or more from scrimmage and had drives of 19 and 16 plays that resulted in field goals.
"The balance is what scares you [about Penn State]," said Hawkeyes coach Kirk Ferentz, in Florida preparing his team for the Outback Bowl. "Their balance can hurt you in so many ways. The line is veteran. I thought the key to their season would be how they would play at quarterback. [Daryll] Clark can throw real well, and he can pull it down and run it."
Ferentz said he had seen a little of USC on TV, and he made it sound as if the Trojans could mimic what the Hawkeyes used to defeat the Nittany Lions.
"They don't give up too many big plays," Ferentz said. "They don't give up too many little plays, either."
If you want stars, USC has stars.
Mays and senior linebacker Rey Maualuga are consensus All-Americans. Maualuga and four other classmates -- Cushing, who made one All-American team, and linemen Clay Matthews, Fili Moala and Kyle Moore -- will play in the Senior Bowl next month. That's five starters from one side of the ball that NFL teams deem are among the top seniors in the nation.
"I never had a chance to study the Miami defenses and Oklahoma in 1986. I watched those guys on TV," Oregon offensive coordinator Chip Kelly said. " They [the Trojans] have it all. A lot of defenses have one or two great players. A lot of their guys, if you took them and put them on another team, they'd be the best player. That's pretty impressive anywhere."
If you want numbers, USC has statistics that will leap off the page and stop a ball carrier in his tracks.
Take the pass efficiency defense rating of 81.46. The next closest defense, Florida, is at 94.17, a difference of 12.71 points.
The 122.8 passing yards allowed per game is about 37 yards fewer than the runner-up, New Mexico State.
But how's this to make your calculator hum: The Trojans have allowed 8.28 yards per completion. That's the goal for most defenses to allow per attempt. In fact, that completion average surpasses the current NCAA record of 8.8 yards per completion allowed by 1997 national champion Michigan.
Between the sidelines, what all those numbers mean is speed and sure tackling, the two pillars of a great defense. USC does not allow receivers to gain yards after the catch.
But the best defense? Ever?
"Statistically, we had a great year," Carroll said. " We're proud of all that they have done. But I don't know about that [best ever]. I wouldn't even know where to begin. Back there in the old Oklahoma days when they won all those games in a row [47 straight during 1953-56], they played some pretty darn good defense. They named defenses after them. You don't hear of any Trojan Defenses out there."
Joe Paterno has been teasing his players to defend the glory of the '47 Nittany Lions, who led the nation by allowing only 76.8 yards of total offense per game. Only once in the 61 seasons since has an opponent led the nation by allowing fewer than 100 yards per game.
Too esoteric? There's the 1988 Notre Dame team, which started four defensive players who became All-Americans before their careers ended.
There are the 2004 USC Trojans, or that 1986 Oklahoma team built around All-American linebacker Brian Bosworth, and the 1959 Syracuse defense that allowed 19.3 rushing yards per game. National champions, all three of them.
USC can't achieve that goal by shutting down Penn State. The other goals are available. While the Trojans aren't likely to shut out the Nittany Lions, much less prevent them from crossing midfield, the onus is on Penn State to prove it can move the ball.
Ivan Maisel is a senior writer for ESPN.com. Send your questions and comments to Ivan at email@example.com. His new book, "The Maisel Report: College Football's Most Overrated & Underrated Players, Coaches, Teams, and Traditions," is on sale now. For more information, go to TheMaiselReport.com.