Nadal's the best player in history on [clay], and he is one of the best-ever players that played this game.

I cannot guarantee anything.

I've had my ups and downs in my private life.

Serbian history tells that family is the most important thing and you have to stick with the family.

You can not say you're unhappy because you have to travel, have to play this tournament, having to play sports ... You can't because you chose to play it and you love it. I'm tremendously grateful for the support I have received from my family and the close ones.

It gives me goose bumps and little butterflies in the stomach when I start thinking about the 'golden slam.'

I don't think, that you can always - you can ever - get your game to perfection, you know. Only if you're Federer.