You only needed to hear her grunt to know that Serena Williams was back to her best. If further proof was needed, the American obliged by showing the door to fifth seed Nadia Petrova despite being a set down and a break down in the second set against the Russian in a third round match at the Australian Open. 

The score line of 4-6 7-5 6-3 may look deceptive, but Serena battled hard to book a place in the fourth round of the Australian Open. Winner at Melbourne in 2003 and 2005, Serena has struggled for fitness, forcing her to rest for most of last year. Even her comeback seemed to be in doubt as many were skeptical on whether she had the hunger to succeed.

But in a grueling two hours and five minutes on Rod Laver Arena, Serena proved that she still has the fire within her. She was 3-1 down in the second set and it looked all over, but some stunning shots saw her serve out the set at 5-4. The win means that she has overcome the first big hurdle in her hunt for a title and may possibly set up a match with Jelena Jankovic.

Elsewhere fourteenth seed Novak Djokovic booked a place in the fourth round with a clinical 6-3 6-4 5-7 6-1 victory over Danai Udomchoke of Thailand. Djokovic will play either Swiss ace Roger Federer or Russian Mikhail Youzhny in the next match.