I am backing Wawrinka in this one, as he is slowely coming back, and he showed in the match against Nadal, his firepowe is still there, he just needs to trust it more,when he does he is practically unbeatable. I see him overpowering Diego, pushing him far back where Diego can do much. As said before Diego became a solid player on every surface in this season and certainly is going to be a tough nut to crack, but I see not beeing able to anwser to Stan's power. So basically see this going in the direction of Stan the man