Game, singular? What game? The 2012 conference title game?
I went back and looked up some of Bo's primary blowout losses:
-2011 --> Wisconsin beats us 48/17, Michigan beats us 45-17
-2012 --> Ohio State curb stomps us 63-38, then Wisconsin embarrasses us 70-31 in the conference title game
-2013 --> UCLA hangs 504 yards on us and beats us 41-21
-2014 --> Wisconsin beats us 59-24 (defense was actually pretty good that season, though)
So I would still disagree with your "I think just the opposite is true" comment, but looking back on it, I think I'd agree that Bo was solid defensively outside of the "big" games that he really needed to win to turn a corner to get the team to an elite level.
It was interesting to look at the stats from the regular season game we had against Wisconsin in 2012 when we beat them 30-27; they only had 56 yards rushing. Makes it that much more bizarre that they then rushed for 539 in that title game. That game was the beginning of the end for The Guido.