Roger Federer discusses his US Open victory over Steve Darcis and insists he still doesn't know when he'll hang up his racket. 

Federer said: "Very often I started this tournament quite strong. It's always gone quite well for me. I've always enjoyed conditions here, the balls, the speed of the court, the atmosphere in the arena. It's always worked very well for me.

"I think this year is another good year. Doing the right things on the court. Like you said, it was pretty on the easier side, you know, so I was able to mix it up, was attacking, was also staying back some. I was pretty much all-out attack as much as I could. Obviously I have to manage that against different players when the scoreline isn't maybe so one-sided."

How long do you want to play for?

"No, not really. I wish I knew. It would make my life easier. But I don't."