World number eight Petra Kvitova’s Australian Open preparations were dealt another blow yesterday 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.