Isner was awesome.
BUT this match basically puts to rest the idea that Fed's lack of Davis Cup success is all to do with the weakness of Switzerland's team - he just doesn't care. There was no fight from him at all in that 4th set - even if you're 2-5 0-40 down you still fight for every ball - it seemed like Fed had decided it wasn't his day and he was okay with losing. Compare this to Nadal at RG vs Isner - sure RG is more important but this was not an inconsequential match. Fed knew Switzerland's hopes in the tie rode with this match (and along with it any outside chance he had to finally get the Davis Cup) yet he just did not put in the effort.
His comments yesterday about it not mattering if they won/lost said it all. He doesn't think that Davis Cup, one of the oldest and most prestigious competitions in the sport, matters that much. There's not much lacking in Fed's record but the Davis Cup will stay there and he's got himself to blame a lot.
Let's see how he does at the Olympics - the other missing title - wouldn't be surprised if someone like Isner took him out there too - especially in a best of 3...