Man, talk about physicality and big bodies in the paint. A tough, tough series of events to officiate. I can see why these guys make the big bucks. Having said that, I'm going to dissent here.
If I were ND's coach, I'd be asking precisely what #45 did wrong on this play.
First, he can't even see LOU5, who comes flying in - so not sure how you can make the call that ND45 undercuts him.
Second, if ND45 moves backwards, it's a combination of moving slightly backwards to try and get the rebound - and being helped by LOU44 tangling up with him and/or pushing him backwards with a forearm.
You basically have ND45 get tangled up with two red bodies on this play - neither of which is his fault, IMO.
Even at this level, I say call the obvious. Foul on Louisville #5.
Whatever the case, I'm just glad I didn't have to clean that mess up. Sheesh