The tennis ball doesn't know how old I am. The ball doesn't know if I'm a man or a woman or if I come from a communist country or not. Sport has always broken down these barriers.

The only people that really have a chance against Serena [Williams] are people that are strong, that can handle her power that move well, and that's a difficult combination.

Concentration is born on the practice court... you must mentally treat your practice sessions as matches, concentrating on every ball you hit.

What matters isn't how well you play when you're playing well. What matters is how well you play when you're playing badly.

Security used to be an inconvenience sometimes, but now it's a necessity all the time.

I think retirement beats the heck out of life after death, that's for sure.

Tennis has given me soul.