Tennis has given me so many opportunities, and I feel very lucky to have achieved whatever I have, especially coming from a country that does not have a great history in the game.

Coaches were all saying that I was really talented and I had potential, but coming from Serbia, it wasn't easy. The '90s were the hardest years for our country - we went through two wars.

Everyone wants to be happy - people find happiness in different ways. While you want to pursue your career 100 percent, I think it is very hard to give 100 percent in something else. It's important to find this balance, and priorities change throughout life.

I think it's better not to mix professional life and personal life - although it is hard.

I grew up playing basketball in the inner city of Seattle, and by the time I was a senior, I earned a full scholarship to the University of Denver.

As a professional athlete, part of my job is to make sure I'm consuming high quality nutrients.

By the time I was 10 years old, my entire life was football. Training, reading, watching, even playing football on PlayStation. I was totally focused on it. I especially loved the creative players - the maestros.

I'm surrounding myself with people who want to do what I want to do, which is be a football player.