Re: If Nadal comeback at his best level, who can stop him except Djokovic ?
Who can stop Nadal except Djokovic?
On clay: Nobody. Maybe some coincidence in circumstances (weather, rival in super form, bad day for Nadal, etc...something like in 4th round 2009)
On grass: During early rounds he is quite vulnerable, but later - maybe Federer in 2012 shape or Murray with more confidence...
On HC: Imo it quite depends on the fastness of the court. Maybe I´m wrong, but I actually can see quite a lot players, who can beat Nadal on HC. The main assumption necessary to beat him is very solid first serve and not many unforced errors (as we could see in IW match with Gulbis, who was close to beat him). At these conditions, he can be beaten by Federer, Murray, Del Potro, Berdych or even Tsonga. But in real world, these players quite rarely perform at their best against Nadal.