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.
You feel better about yourself when you do something with yourself. You also feel more confident.
I do my best, and that's all I can do.
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.
To be the world No. 1 has always been a dream for me.
I'm the type of player I am.
I think I'm a really tough player.
You can't dwell in your past but move forward, look forward. That's it.
I feel like everything is possible.
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 just go out there and fight for every point, and then we see how far I can go.
There are so many tough opponents out there and tough competitors so I've never liked to look ahead.
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.
My mom was always the support. I can always go out to her and she'll always find the positive in things.
My parents just always taught me to be reasonable.
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's just nothing like playing on Arthur Ashe Stadium. It's truly amazing.
I love winning. I don't like losing.
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.
Golf can be tougher than tennis when things go wrong, because you can't explain things by saying that your opponent played better than you. It's a cruel sport in that way.
It's very expensive to be a professional tennis player with all the travel and the flights and the hotels and everything.
In Denmark lots of people come up to me for autographs.
I start laughing every time because the media talks to me like I'm finishing my career and I only have one year left and time is running out.
Follow AzQuotes on Facebook, Twitter and Google+. Every day we present the best quotes! Improve yourself, find your inspiration, share with friends