I am two different people. What you see on the court is just natural for me. I wear my heart on my sleeve. I have always said Cmon purely to fire myself up. Off the court, I am a lot shyer. I stick to my team and my family and people I trust.
That's when you've got to grit your teeth and hang in there and try and find a way to win when you're not playing your best tennis - that's what I can be proud of
When I go out to play, I still believe I'm as good as anyone out there. I don't have to prove anyone wrong. I know what I've done and how well I can play.
When I was a kid in Adelaide, I dreamed of becoming No. 1 in the world, winning a grand slam and the Davis Cup for Australia.
Matches are won and lost so many times in the locker room.
Everyone has to call 'time' at some stage.
Even when I was No. 1 in the world, I was taking it one match at a time. I never was a player to look too far ahead, the way draws can pan out.
That's what you do all the hard work for, to play in situations that put your body through gruelling times. If you're not up to it, pull out.
I'm fortunate: I can play as long as I want to play. There's no coach or trainer who is going to say to me that I'm dropped or sacked, it's time to move on. I can play as long as I want to play.
I'm not a guy who needs to read motivation books.
I'm one injury away from hanging up the racket at any time.
I was lucky enough to win the Davis Cup in my first year in 1999. I won my first slam at the U.S. Open in 2001 and became world No. 1 later that year. By the age of 20, I'd done it all.
Oh, I get pretty fired up on the court. I try to play with a lot of emotion, especially when I'm playing in front of a large crowd. I want to go out and do my best, and to do that, I have to play with the most energy possible.
I'm more in that Rafa Nadal high-energy high-octane mold out there. I wear that emotion on the court. That's how I play my best tennis. People either like that or not. And I can't change that: that's who I am on a tennis court.
My video game character is a bit better looking than me, actually. I don't think he has to worry about his hair getting messed up.
I feel like when I'm match tough and match hard and played a lot of matches I got that competitive winning spirit going and I can get on some rolls like I did last year. I won San Jose, Indian Wells and made the semifinals in Miami so it can happen for me.
I liked Pat Cash, and I loved Mats Wilander. I went to the Australian Open with my parents, and I used to watch Wilander being cheered on by the Swedish fans, and with his game style being like mine, I drew comparisons with him.
Maybe I have to work a bit harder on clay. It's a challenge and I've always liked challenges. Whether I will ever win the French and master playing on clay, who knows? But I'll give it a shot.
I don't know. Haven't I always been mature?
I'm not to eager to play tennis in my spare time. I'm more interested in doing gym work and stuff like that. We have a lot of schools and courts around where I live, so if I really want to play, I don't need to go too far.
I'd much rather win in three or four sets than go the distance all the time; I seem to put everyone through the wringer quite a bit.
I have sometimes played my best Davis Cup matches away from home when you stay in the moment a bit more. But it is tough when half the crowd are spitting on you.
There are people who love you and people who hate you, but for me, more so, people only think they know me by how I act or perform on a tennis court.
Grand Slams are different. If you can get through a few matches, the draw opens up and you get confident. You just need a little bit of luck early, you get through those opening matches and you never know what could happen.
You always love playing in finals at any tournament. The grand slams and stuff like that are obviously the priorities but any titles go on your record.
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