It funny how you say that. But if Nadal had been in top form, he would have destroyed Murray.
Nadal had one of the worst games of this year. He's is exhausted ( after winning every grand slam ( not counting Australia ) and SPTs and then going off to get gold in the Olympics. Did Murray do that? No ) and his accumulated fatigue was a real factor in the game. Never before has Nadal made so many unforced errors. There was something wrong with him last night, he wasn't himself.
Saying that, Murray had a tremendous game ( he had to have that, to beat Nadal, even when he was playing poorly ) and really showed how good he can be. There will be more times when these two meet, but for now Nadal can rest and relish the epic year he has mounted. He is the best tennis player in the world, and one defeat will not change that.