Hard-court is his best surface, right?
As we've seen just this year, things can change on a dime.
Both true statements, but last year at this point Djokovic had won everything except Roland Garros, including beating Nadal in the Rome final. It's clear the landscape is completely different and Djokovic after losses to different players (Fed, Nadal, Murray, Isner) doesn't have the invincible aura he had last year. He still might be generally considered the guy to beat though, depending how he does in the US Open (series), as Fed's #1 ranking is a bit a result of "tournament whoring".