World No.14 Elina Svitolina has become the second high-profile woman to withdraw from the Sydney International just hours into the opening day of the tournament.
The sixth seed cited a viral illness for her decision to pull out of the Australian Open warm-up.
“I’ve had constant headaches for the last two days and unfortunately in today’s hot weather it got even worse when I was warming up and my body wasn’t ready to compete,” Svitolina said.
“I love playing in Sydney, it’s one of my favourite stops during the season. Hopefully I can come back next year and play in front of the amazing fans here.”
Svitolina’s withdrawal comes on the back of recently-crowned Brisbane International winner Karolina Pliskova’s resignation on Sunday morning due to a thigh injury.
Veteran Svetlana Kuznetsova became the first woman through to the second round after defeating Romanian Irina-Camelia Begu 6-1 6-4 on Ken Rosewall Arena.
The world No.9 will now play either Australian Samantha Stosur or Russian Anastasia Pavlyuchenkova.