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

I've had a lot of fear in my life, from fear of flying to fear of making a speech in front of a lot of people.

If you can react the same way to winning and losing, that's a big accomplishment. That quality is important because it stays with you the rest of your life, and there's going to be a life after tennis that's a lot longer than your tennis life.

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.

Relationships are give-and-take, and when you're a tennis player, you're certainly not giving. You have to be self-absorbed. It has to be about you.

When I play, I'm boiling inside. I just try not to show it because it's a lack of composure, and if you give in to your emotions after one loss, you're liable to have three or four in a row.

You're always striving to play that perfect match.