Bottom line is Fed has clearly shown that he is prone to mental lapses during matches now. Especially against players who he fully expects to win against. I think he did so well in the AO final because actually perceived Murray as a serious threat and so was fully focused for that match. Plus he lost last year's AO so probably really wanted to win it again. In contrast, against Delpo in the USO final, he probably expected to win and just lost focus and couldn't lower the hammer when he had opportunities to do so in both the 2nd and 4th sets. Same thing has happened for the last 2 months. He goes into these matches and then loses focus. Hence, it's actually more likely that he loses against some of these dangerous but inconsistent players like Gulbis and Delpo than proven threats like Djokovic and Murray. Because I really don't think he's lost anything physically in the last year or so. I think the Fed we see today is the same one we've seen since middle of 2007. Fed from 2004-2007 (that Fed is the true GOAT) is long gone but Fed from 2008-present really hasn't changed much. When he experiences his next significant decline then I think he will retire shortly thereafter. But he takes care of himself so I think he can maintain this for another year at least.