Serena Williams is some way off her best form but she has still able to shut out Andrea Petkovic at the Brisbane International.

Top-ranked Williams was understandably below her best after the offseason but fought hard to overcome Petkovic, who has a career-high ranking of No. 9.

Williams now progresses into the quarterfinals and will not be celebrating New year's Eve as she prepares for the Australian Open.

"I don't celebrate New Year's Eve, so usually I'm in bed at midnight," Williams told the WTA.

"I'm a very serious player. I never leave my room during a tournament, so I'm not going out."

Federer eases into next round

In the men's singles, home favourite Lleyton Hewitt defeated fellow countryman Thanasi Kokkinakis 6-3, 7-5 and Nicolas Mahut of France came from behind to beat Igor Sijsling of the Netherlands 3-6, 6-4, 6-4.

Fourth seed Jelena Jankovic defeated Elina Svitolina of the Ukraine 61, 6-3 in the women's singles whilst Sloviaki's Dominika Cibulkova, Slovakia sent Japan's Kimiko Date-Krumm out of the tournament 6-3, 1-6, 6-3.

Roger Federer won his first match of the season with Nicolas Mahut of France as they teamed up in the men's doubles and eased to a win over top seeds Jean-Julien Rojer of the Netherlands, and Romanian Horia Tecau 7-5, 7-6 (5).

Federer played with a newly designed racket featuring a larger head in a big to reverse his 2013 fortunes, which was his worst season in over a decade.

Jamie Murray of Britain joined forces with Australian John Peers to beat Eric Butorac of the United States, and Raven Klaasen of South Africa, 6-3, 6-4.

Source: Al Jazeera and agencies