batz
G.O.A.T.
Very likely. Del Potro doesn't seem like a head case who will just go out in the early rounds. Consequently, he has shown that he can now beat the top 2 players in the world regularly. Not many other pro's can boast about that.
Just think about that for a minute will you. You are implying that Borg, McEnroe, Lendl, Sampras, Agassi, Federer, Nadal etc.were all headcases because they didn't win the following slam after winning their first one.
The reason they didn't do so is because it is such a hard thing to do. That is as true today as it was back then. That makes your assertion that Delpo is 'very likley' to win back to back slams look a bit weak. If he does it them maximum kudos to him.