I'm thankful to be able to team up with a company like USANA that cares about my well-being and I know we can do great things together.
I never give up. Doesn't matter what the score is.
The only one I feel pressure from is myself to go and give my all for every match and, obviously, I'm a competitor.
My parents paid me small amounts for cleaning my room or cleaning the dishes and stuff, but I never really had a real job before I started on my professional tennis career.
I'm the type of player I am.
I think I'm a really tough player.
To be the world No. 1 has always been a dream for me.
You can't dwell in your past but move forward, look forward. That's it.
My dad has always been my coach. And I've spent so much time with him. So he's one of my best friends. And I can talk to him about everything.
I feel like everything is possible.
I just go out there and fight for every point, and then we see how far I can go.
I do my best, and that's all I can do.
There are so many tough opponents out there and tough competitors so I've never liked to look ahead.
I love winning. I don't like losing.
I try to be myself and, of course, be a good role model. I don't really find it hard, but you think about what you do and that other people look up to you.
I believe the best in people. I believe if you need a bathroom break you go to the bathroom. If you need treatment, you get treatment. I don't think any rules should be changed.
There's just nothing like playing on Arthur Ashe Stadium. It's truly amazing.
I have proven people wrong so many times. I was told when I was younger there is no chance I will make the top 100, top 50, top 30. Every time I have proven them wrong. It's kind of nice.
Young players are starting to come up as well and they will see me as one of the older, experienced ones.
I don't know, I always get the question 'how do you feel after the game today?' and, of course, if you're winning you feel great and if you lose you don't feel good. I think that's a pretty obvious question.
I don't really spend money like crazy. I buy what I need and what I really want, and if I'm buying expensive things I do think about the purchase many times before I buy it.
There are a lot of things to my game I can still improve, but everyone can.
You feel better about yourself when you do something with yourself. You also feel more confident.
One day my dad would say, 'OK, if you want to play tennis I can help you out.' And that's how it started. And I had a goal. I wanted to beat my mom first. And my parents and my brother. And that was the ultimate goal.
The fact is I still have quite a few good years in front of me. I still improve.
Follow AzQuotes on Facebook, Twitter and Google+. Every day we present the best quotes! Improve yourself, find your inspiration, share with friends