Former French Open runner-up Sara Errani is the second woman through to the quarter-finals of the Sydney International with a tight twin-tiebreaker win over former world No.1 Jelena Jankovic.

Down 5-2 in the second set, the Italian world No.19 fought back to win 7-6 (7-3) 7-6 (10-8) and book a date with Germany’s Sabine Lisicki or Svetlana Kuznetsova of Russia.

Earlier, world No.10 Angelique Kerber was the latest woman to pull out from the Australian Open lead-up event, citing gastrointestinal illness.

The 27-year-old German won her opening match of the tournament on Monday, defeating Ukraine’s Elona Svitolina 4-6 6-0 6-3.

But the Brisbane runner-up joined a growing list of Sydney withdrawals on Tuesday, including defending champion Petra Kvitova (illness) and world No.5 Agnieszka Radwanska (leg).

She is the final member of the women’s top 10 who has suffered a pre-Open setback in the past week.

“I’m very sorry I can’t go on court today but I’m not feeling 100 per cent. I started to feel unwell yesterday and today my stomach is not right,” Kerber said.

“I don’t want to risk my health before Melbourne, of course, but I love to come back to the Apia International Sydney and always have good results here – semi-finals last year and the final two years ago.”

Australia’s Hopman Cup winner Daria Gavrilova was also a late scratching due to an abdominal strain.