It is clear to everyone that Djokovic has increased his level while Federrer and Nadal have somewhat decreased it.
However, so why Djokovic is unlikely to win the US Open 2011?
As Federer is getting old and has less energy and Nadal is always recovering from injuries their are many players that have all the potential to knot out a Djokovic maybe over-confident and slightly burnt out of his fantastic season. And many of them are there.
