McD said the poor run defense it was about "fundamentals" and "technique" and only mentioned the usual culprit, a bad "fit", on the long run right after halftime. To me, that sounds like it's about the players getting handled and not about scheme errors. So I don't think that's something you can easily fix in a week. They either need to change the scheme, get new players, or wait for their current players to gradually improve over several weeks.