You are coming to this conclusion based on his recent form(IW, this match)? Really? He was so much better in the AO, that's pretty clear.
Do you seriously believe that even that Wawrinka will go toe-to-toe with a healthy Nadal when the latter start grunt him into oblivion even if he was down 2 sets? do think Wawrinka, as first-time Slam Finalist had the mental package to outlast Nadal there, against whom he was 0-12 H2H; 0-28 sets (he was already wetting the pants when Rafa mustered some pluck and went all broke while half-crippled in the 3rd set)?