I can definitely say the same thing [discussing Steffi Graf's claim that she had played against at least one top player who used steroids]. Steroids can really make a difference, physically and mentally. I'd be really disappointed if I had been ranked No. 2 behind someone who took steroids.

Ninety percent of my game is mental. It's my concentration that has gotten me this far. I won't even call a friend on the day of a match. I'm scared of disrupting my concentration. I don't allow any competition with tennis.

Ninety percent of my game is mental. It's my concentration that has gotten me this far.

I still have this image: I can't be controversial, I can't say things.

In tennis, at the end of the day you're a winner or a loser. You know exactly where you stand... I don't need that anymore. I don't need my happiness, my well-being, to be based on winning and losing.

When I was younger, I was a robot. Wind her up and she plays tennis.

If I win several tournaments in a row, I get so confident I'm in a cloud. A loss gets me eager again.