I think it is problematic moving forward that the two safties are 1 and 2 in tackles. The LBs and DLs have to step it up against Michigan, MSU and especially USC. Toryan was the leading LB in tackles with only 5. B Smith had only 3 tackles on the day. That's only 1 more than Manti who got very limited action.
If ND had played a Woody Hayes 3 yards and a cloud of dust offense it would be a concern. Back in the days when team ran 70 or 80% of the time. But ND didn't play a "pound it" offense. They played a team with a pair of 1,000 yd "Big Play" rushers. Oh, and one of them passed for almost 3000 yds last season.
ND played with an extra DB and one less player in the Front 7 you're worried about. Yes McCarthy lead the team in Tackles with 9 and Harrison Smith had 6 while Toryan had 5. Not an order of magnitude to be concerned with ordinarily but even less considering that Brian Smith was assigned to "Shadow" the QB, Kaepernick. Brian only had 3 tackles, OH Disaster! Except that he had 2 TFLs and a Sack and held his 1000 yard rusher to 39 yards rushing and disrupted their passing game. As did his fellow LBs who were frequently blitzing to disrupt NV's game.
McCarthy had 9 tackles and if you check the play by play you'll find he only had 3 stops on runs. The majority of his tackles, 6, were on passes. Why is that unusual for a Safety?
Nevade ran 29 times and passed 27, almost a 50/50 mix. ND played a total of 6 DLs, 6 LBs, 3 Safeties, and 4 CBs (Sergio started as a Nickel Back and is listed as a CB in the Official stats. Here's the Tackle Breakouts:
6 DLs 11 Tackles
6 LBs 17 Tackles
3 Ss 16 Tackles
3 CBs 9 Tackles
Front 7 28 Tackles
Secondary 25 Tackles
ND assigned Brian Smith to shadow Kaepernick, the DEs were supposed contain, to turn plays in, and and use the field to ND's advantage. It worked.
NV had 10 drives:
#Plays-Yds-Result
8-52 Missed FG
3-6 Punt
3-5 Punt
7-37 Downs
8-42 INT
5-33 Punt
4-20 INT
7-54 Fumble
7-33 Punt
5-6 Punt
Let's give some credit to the opponent's rushers. They must have some talent to both be 1000 rushers. They made a couple of nice runs - none of which hurt ND. ND made them "play between the 20's". They only reached the Red Zone twice and came up empty both times.
Navy's option frustrated the OSU defense and burned them. Navy's QB had the 6th most efficient passing day in FBS. Navy's players don't have the talent of either Kaepernick or Taua.