SOUTH BEND, Ind. (AP) Sixth-ranked Notre Dame faces a lot of unanswered questions through four games of the season.

The Fighting Irish (4-0) have won two straight starts by quarterback DeShone Kizer, and he rallied Notre Dame with 12 seconds left to beat Virginia three weeks ago. But how will the sophomore react to a raucous crowd in his first road start at No. 12 Clemson (3-0)?

Will the Irish defense, which seems to alternate between dominant and susceptible to big plays, find a way to play consistently well? Will the secondary continue to be burned by gadget plays?

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But the biggest question facing the Irish: Just how good are they? It's hard to say. Notre Dame's victories have come against opponents with combined records of 4-11.

A 30-22 victory against No. 14 Georgia Tech two weeks ago doesn't look quite as impressive after the Yellow Jackets were beaten 34-20 by Duke on Saturday. Notre Dame heads into Clemson looking for their biggest road win since a 30-13 victory at Oklahoma in 2012 solidified their position as a national championship contender.

Kelly said at his weekly news conference Tuesday that what he is most confident about is team chemistry.

''It's a close team. They'll play hard for each other. There's no quit in them. They'll overcome adversity,'' he said.

The Irish already have overcome adversity with six players out with season-ending injuries, including quarterback Malik Zaire and running back Tarean Folston. Kizer at quarterback and C.J. Prosise at running back have done well replacing them. Prosise has rushed for 600 yards - the most ever by an Irish back in the first four games of a season. But both lack experience at their positions.

''We're still learning about the players that have had to come in and step in after these injuries,'' Kelly said.

Injuries finally caught up with the Irish last season after a 6-0 start and a near-upset at No. 2 Florida State. Notre Dame lost five of its last six regular-season games.

But the Irish know they can run the ball, ranking 12th in the nation at 285 yards a game. They are 15th in total offense, averaging 531 yards, which is on pace to break the school record of 510.5 yards a game set in 1970.

They know they have an elite receiver in Will Fuller, ranking third in the nation with six touchdown catches, eighth with 454 receiving yards and 11th in receiving yards per game at 114.

What they don't know is how they will do on the road. The Irish had lost five straight road games until Kizer threw a 39-yard TD pass to Fuller with 12 seconds left to give Notre Dame a 34-27 victory at Virginia three weeks ago.

The Irish are 2-5 under Kelly on the road against ranked teams, with both wins coming in 2012 at No. 10 Michigan State and No. 8 Oklahoma. Clemson is 41-6 at home in seven seasons under coach Dabo Swinney and have won 11 straight at home.

Kelly said he expects the Irish to respond like they did last season when they nearly upset No. 2 Florida State, losing on a controversial pass interference call that cost them a touchdown with 13 seconds left.

''I think we'll have a lot of carry over,'' Kelly said. ''We'll talk in terms of the same kind of environment ... in terms of how we'll need to prepare.''