Brisbane: Wimbledon runner-up Sabine Lisicki of Germany has pulled out of the season-opening Brisbane International due to a gastrointestinal illness.
The seventh seed was due to meet Swiss player Stefanie Voegele in the second round on Wednesday.
Voegele now progresses straight to the quarter-finals where she will play the winner of the match between second seed Victoria Azarenka and Australian wildcard Casey Dellacqua.
Meanwhile, Lisicki`s fellow countrywoman Angelique Kerber moved into the quarter-finals when her opponent, Anastasia Pavlyuchenkova, withdrew during their second round match with an injured left thigh.
Fifth seed Kerber was leading 6-2, 4-3 when Pavlyuchenkova, who appeared to injure her leg early in the second set, was forced to concede.
Kerber will take on fourth seed Jelena Jankovic in the quarter-finals.