Notre Dame won that game because of poor coaching decisions on MSU's part. They didn't run at the right times, they didn't pass vertically (more horizontally), and they should have run more often than they did. They were running all over ND and decided to air it out a few times, horizontally I might add, and that never worked. On top of that, the last 3 possessions for MSU were all turnovers. MSU let ND get back in that game. ND didn't get back into it themselves. Also, there were quite a few muffed up plays where some people just didn't know what they were doing on MSU's side.
I'm personally feeling a Auburn/Michigan national title game. OSU wasn't impressive against PSU, and I also think Michigan will just flat out beat OSU to get into the national title game against the other undefeated team, Auburn, who I feel will beat both Florida and Georgia down the stretch.