SOUTH BEND, Ind. -- Talk about going on the defensive.

The biggest task Saturday for the nation's No. 1 team is stopping the nation's top receiving duo, and a pair of former offensive players are the guys Notre Dame will again be counting on to deliver one last regular-season stand.

Corners Bennett Jackson and KeiVarae Russell joined the Irish at receiver and running back, respectively. Together they have shored up what was the biggest defensive question mark entering this perfect campaign, resulting in the nation's top scoring unit (10.09 ppg).

Yes, USC's quarterback will be making his first career start. And he has not been shy about wanting to make a first impression. But the moxie of Max Wittek likely derives from the guys he will be throwing to.

Marqise Lee is the nation's top receiver (107 catches for 1,605 yards). Robert Woods isn't too shabby himself, and if this year's numbers can't prove that (66 for 721), last year's certainly can (111 for 1,292).

"There is only one football, so it just seems like he's gotten more of the catches, whether by design or not," Notre Dame coach Brian Kelly said of Lee. "Either one of those guys can beat you by themselves. The numbers just have gone his way this year."

Or, as Jackson put it bluntly: "USC's receiving corps is on another level."

For the Irish, keeping the points down is more important than keeping the stats in line, as evidenced by their Oct. 27 win at Oklahoma, which had a 356-yard passer and a 181-yard receiver but managed just one touchdown.

The key? As Kelly said earlier this week when asked about defending big-play wideouts: tackle, tackle, tackle, tackle and tackle.

Notre Dame, according to ESPN Stats & Information, has just 55 missed tackles this season, the third-fewest among BCS schools. Irish opponents have completed just 7 of 41 pass attempts of 20 or more yards, resulting in one touchdown and four picks.

"You get a feel for it," Jackson said. "You let them get their few little short routes and then if they keep running, then eventually they're going to jump one. But I feel like as we get close to the goal line, we become more confident that they're not going to score. The space becomes more limited, and at the end of the day those short routes aren't going to be what wins the game.

"Big plays are game-changers. Those two guys did a great job running past the defense and getting the ball behind the defense. If we keep them in front of us and make our tackles, we'll be fine in the secondary."

The Oklahoma game, like most, was Manti Te'o's time to shine, with the Heisman candidate notching 11 tackles and a game-sealing pick. But Russell and Jackson were the team's next two-highest tacklers, with nine and eight, respectively.

Fewer swings and misses on the defensive side should test the 19-year-old Wittek's patience as USC drives down the field.

When that happens, Notre Dame's last line of defense will be in its most comfortable position.

"They're going to throw it up," Jackson said. "They're going to let their guys make plays, and it's going to be down to the guys back there to win the battle for the ball."