The US player Andy Roddick reaches speeds of 220 kilometers per hour when he serves. If I train with him every day, I will later be at an advantage against a player whose service crosses the net at 190 kilometers per hour.

My serve can get better, for sure. It's not just about serving bombs, but positioning, variation in speed, in spin.

A lot of times I had some problems, but I always had the passion and the personal motivation to keep going, to keep working hard, keep fighting for the things that really motivates me. That's all.

Stay healthy, do sports and above all have fun while doing sport. Competing or just for fun, whatever, simply enjoy and try your best. Working hard, working well with achievable goals normally pays off. Believe in the people that are with you and listen to those who have more experience.

I'm only superstitious on the tennis court.

I used to wear sleeveless T-shirts all the time on court, but now I've got a brand new look - I've moved on to polo shirts. Sleeveless T-shirts give you real freedom of movement and they keep you cooler in matches, but I just thought it was time for a change.

In your career you have a lot of good moments and bad ones. The important thing is to have enough motivation to keep working all the days with humility and trying to be a better player than before. I am going to try to continue doing this.