The Buckeyes lost to Va Tech in the second game of the season in 2014. Okay, not the first game of the season, but our first game was against Navy, so it kinda was. And it was a loss at home. Those are really hard to overcome in the eyes of the voters.I don't know if a team ever lost its opening game and then still won the NC or not.
In the CFP era, you need to have 1 loss or fewer and win your conference. So all that an early loss does to a team like Alabama or FSU is remove the safety net.