The speculation above regarding how SU's defense will hold up against ND's offense is not the biggest concern imo. ND is 9-0 and in the top 4 because of their defense. Their front four (and their replacements) can put a lot of pressure on a QB without the help of a blitz. Their back seven are very fast and they're good tacklers. The two corners are shutdown guys that will play in the NFL and the safety (Gilman) is all over the field making plays.