The thing about tennis is if you stay off for two weeks, or just for three days, you can lose your rhythm quickly. So it's just a question of constant diligence and vigilance.

Everything is tennis for me, it's my career and it's entertainment, but it's also a business.

Sport teaches you so much, and you can translate that to other parts of life. But it's definitely a lot of dedication, not just for, you know, myself or the children, but the parents, the family finances, the money that you could be putting toward retirement you're using to buy tennis shoes and restring rackets and tennis lessons. So if you don't make it, then you may never retire. It's definitely a lot of risk.

I think nowadays it's so easy as an athlete to become a statistic whether or not you lose everything or having trouble or whatever it may be.

For years I felt that I didn't have enough stamina and then, four years ago, I felt like I was not getting enough air but I was diagnosed with exercise-induced asthma. The medicine for asthma never worked.

Losses have propelled me to even bigger places, so I understand the importance of losing. You can never get complacent because a loss is always around the corner. It's in any game that you're in - a business game or whatever - you can't get complacent.

I truly believe that whoever feels the most confident is usually the one to win.