Defending champion Petra Kvitova and second seed Agnieszka Radwanska have been forced to withdraw from the Apia International Sydney.
Kvitova, the world No.6 and third seed, is suffering the lingering effects of a gastrointestinal illness while Radwanska withdrew citing a left leg injury after winning the WTA title in Shenzhen on Saturday.
Kvitova expressed her sadness on Sunday at having to drop out of the tournament.
“I’m really disappointed to have to withdraw from the Apia Sydney International but unfortunately I am still not feeling well,” she said.
“Being defending champion, this tournament obviously means a lot to me and I’ve always had a wonderful time playing this event.
“I look forward to coming back in future years to play for my fantastic fans.”
Kvitova has been replaced in the draw by lucky loser Polona Hercog, while qualifier Daniela Hantuchova has taken Radwanska’s place.
Another lucky loser, Lucie Hradecka, has also been elevated into the main draw.