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.

I think team sports probably teach you more about giving - about being unselfish and being flexible.

Single-mindedness. I hate to say it because I don't think it's the best thing for developing a person, but the single-mindedness - just concentrating in the one area - that's what it takes to be a champion.

Competitive toughness is an acquired skill and not an inherited gift.

Now that I'm losing some, I can see how tough I was -- the killer instinct, the single-mindedness, playing like a machine. Boy, that's what made me a champion.

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.

If you're a champion, you have to have it in your heart. You can have the greatest coaches in the world, all the opportunities to play, and the greatest equipment, but if you don't have it inside, you're not going to make it. On the other hand, if you don't have any of those luxuries but you have heart and courage and the guts to go out there and grind it out, then you'll make it.