Murray is in that bracket too, because he's worked like an absolute demon in the gym over the past 3 years to get to the level of those guys. Who remembers him in those Wimbledon Semi v Nadal where he just couldn't compete physically with the power and the stamina of the Spaniard? Nadal had the massive biceps and Murray looked a little boy in comparison.
Murray's arms and legs are sheer muscle these days. To use a term I hate, he's got a right pair of guns on him now and that is down to sheer hard work. The tennis ability was always there with Murray, the only question was his small frame and lack of stamina to compete in 5 set matches. Those days are gone now, Murray outlasted Djokovic in the US Open Final, Djokovic was shattered and that says everything for me.
Any accusations of Djokovic doping are fecking brainless, these players are tested just the same as any other athlete. He's just a phenomenal tennis player.