My failures were something for me - my first contact with professional football. Though it didn't go all that well, it's not a regret, it's just like that. But looking back, those failures helped me consider football differently, consider the professional game differently.

I can talk with my team-mates, understand them and it's better for understanding the coaching staff and the game itself. If someone's making a run and they shout for the ball, I know now.

I came to Chelsea to work, to keep learning and to keep improving.

Whatever you did in the past is quickly forgotten.

Football's been such a part of my life. It's allowed me to meet so many people and do so many things.

You're going to fail. It's how you respond to that failure that kind of defines you as a person, as an athlete.

Right now, I'm at the top of the world in my game so my focus isn't on when I'm going to end. My focus is on playing the best tennis that I can, and there is no end to that.

I've stayed calm when I'm winning and I've stayed calm when I've lost. Tennis is a sport where we have a lot of tournaments every week, so you can't celebrate a lot when you have big victories, and you cannot get too down when you're losing, as in a few days you'll be in the next tournament and you'll have to be ready with that.