Theoretical back-to-back finals on Sat & Sun isn't what I'd base my opinion on. I think that's irrelevant to Fed. Give me an example of the last time he was too gassed to contend for a slam semi or final.....31 or not. I think his fitness is peerless on the tour. Inherited from a champions lineage via Llendl and Sampras.
Nadal being a bad match up for Fed is a sound basis for further discussion.
Both mentally and physically he Raf has dominated in that match up and I wouldn't bet against him.
Rog v. Nole is a toss in my book at this stage of the game.
If I had to make a choice, I'd side with DJoker though it's hard to count Fed out riding the wave of confidence he has now.
Should be an exciting tourney!

Perhaps this is the year I'll finally see it in person.
