Melbourne - Jelena Jankovic has no time to waste on doubters who suggest that without having yet won a Grand Slam title, she does not deserve to hold the top WTA ranking.

But the determined Serb seems ready to deal with the critics through her racket and won't waste mental energy with the Australian Open starting on Monday.

"I'm just a girl who enjoys her tennis. I go to the court with a smile on my face, and that's what matters," she said. "I don't really think and stress about ranking, Grand Slams, so many other things.

Melbourne - German Nicolas Kiefer on Saturday lost his fight for fitness, withdrawing from the Australian Open due to an ankle injury he suffered a week ago.

Kiefer had been hoping for a miracle recovery after turning his ankle during a match in Perth at the Hopman Cup.

He was taken off of court in a wheelchair and later underwent a hospital scan which showed tendon and ligament damage.

The 31-year-old fell victim to the worst possible luck as he suffered a freak mishap while leading Slovakia's Domink Hrbaty 3-1 in their group match.

Melbourne - Rafael Nadal Saturday followed the lead of Roger Federer, saying he would prefer if the Australian Open were played in February instead of its traditional January date.

"I would love (to) have the first Grand Slam of the season a little bit later," said the top seed. "You start the season and after one week you are playing one of the most important tournaments of the year."

Auckland - Argentine Juan Del Potro resumed where he left off last season, winning the fifth title of his career in the space of seven months with a 6-4, 6-4 defeat of Sam Querrey in the Heineken Open final on Saturday.

The success required less than 90 minutes and puts the world number nine into good position with the Australian Open starting on Monday.

Querrey now stands 1-1 in ATP finals after winning Las Vegas last spring.

Melbourne - Roger Federer dominated good friend Stan Wawrinka 6-1, 6-3, taking just 57 minutes on Saturday to secure his second title in five years at the AAMI Classic.

"I've played plenty of matches going into the Open, the health is not an issue," said the winner. "I'm fresh and fit and ready to go. Things are the way I was hoping them to be."

Melbourne  - Serena Williams Saturday said she plans to spend plenty of time alone in her hotel room, downloading films and TV shows and making her own entertainment in between matches at the Australian Open.

Calling herself "terrible" for Hollywood balance sheets, the three-time champion has become a huge fan of on-demand entertainment.

"I love to watch TV, I've gotten into iTunes," she said. "I'm terrible for the whole music industry and movie industry because I download movies and music and TV shows.