Dont fall into the trap of extrapolating that first play. If Proctor goes for the tackle there, Styles is dropped immediately for a 9-10 yard gain. Proctor was IMMEDIATELY benched after that play. The OSU defense was aggressive and played very, very well in comparison to the last 2 years.
ND was a HEAVY underdog going in. They played better than what the line suggested they would do. You won't face a better defense until you play Clemson. Clemsons offense is not better than OSU's offense. You may not lose another game.