SYDNEY - Defending women's champion Petra Kvitova has withdrawn from the Sydney International, marking the second consecutive week that the two-time Wimbledon winner has pulled out of tournaments due to a lingering stomach virus.

Kvitova retired during the first round of the Shenzhen Open in China last week. She was scheduled to play her first match in Sydney against Germany's Sabine Lisicki on Monday.

Bernard Tomic is the top-seeded man at Sydney, while No. 2-ranked Simona Halep is the top-seeded woman.

There were no ATP matches scheduled Sunday in Sydney.

Ana Ivanovic, who received a wild card, was scheduled to play her first-round match later Sunday against fifth-seeded Karolina Pliskova.

At the Hobart International, another of the Australian Open warm-up tournaments, Russian Margarita Gasparyan beat 17-year-old Australian player Maddison Inglis 6-4, 6-3.