Roger Federer is happy with his form and fitness during the ongoing Australian Open.

The former world number one was speaking following the conclusion of his quarter-final victory over Juan Martin Del Potro earlier today.

"I'm moving well, I'm serving well, I'm hitting the ball clean," Federer told reporters. "Today I thought on a very hot day with fast conditions, I was able to control the ball.

"I didn't really struggle too much on his serve today for some reason. I was able to return great, and I think that was a big key.

"Then I think I was serving the right way, even though I didn't have the highest first serve percentage."

Today's match was Federer's 31st consecutive Grand Slam quarter-final.