SYDNEY: World No. 8 Petra Kvitova’s Australian Open preparations were dealt another blow on Sunday when she was trounced in straight sets at the Sydney International by Slovakia’s Dominika Cibulkova.

Fifth-seed Czech Kvitova, the 2011 Wimbledon champion, continued her form slump in Sydney, losing 6-1, 6-1 to Cibulkova in little more than an hour.

It follows her surprise second-round exit from this month’s Brisbane International, where she fell 6-4, 7-5 to Russia’s Anastasia Pavlyuchenkova, and her withdrawal from November’s WTA Championships in Istanbul due to illness.

“I played really badly and I wish I knew what I could say but I don’t know,” Kvitova said after the Sydney match.

“I’m not feeling very well right now, in my confidence, but I’m always looking forward to playing grand slams and I hope everything will be better there than here.”

Denmark’s Caroline Wozniacki had more luck, downing Urszula Radwanska 6-1, 6-2 in a powerful return to form that saw her take the first set in just 26 minutes.

Russians Maria Kirilenko and Ekaterina Makarova also posted wins, progressing to the second round by overcoming, respectively, Australian wild card Olivia Rogowska 7-5, 6-2 and America’s Varvara Lepchenko 6-4, 4-6, 6-1.

Seventh seed Wozniacki was ousted at Brisbane after an epic first-round battle with Kazakh qualifier Ksenia Pervak, losing valuable practice time for the Australian Open.

The Dane said that she was relieved to notch a win ahead of the season’s first Grand Slam, which begins in Melbourne on Monday week.

“It was quite hot out there, especially towards the end of the second set you could really feel it was starting to heat up,” said the former world no. 1.

Wozniacki said that she was hopeful of regaining top ranking despite an inconsistent 2012, in which she exited Wimbledon and the US Open in the first round.

Wozniacki’s boyfriend Rory McIlroy, golf’s world no. 1, watched her victory from the stands.

The pair fuelled speculation they were engaged last month when Wozniacki was photographed with a large ring on her left ring finger ahead of the Brisbane International.

In November McIlroy skipped the $7-million WGC-HSBC Cham-pions to watch Wozniacki play tennis in Bulgaria, and she then followed him to tournaments in Singapore and Hong Kong.

However, Danish women often wear wedding rings on their right hand, and Wozniacki is also known for her penchant for practical jokes.

McIlroy was due to fly out of Australia on Sunday to start preparing for the Abu Dhabi golf championship later this month.