Wimbledon champion Petra Kvitova has survived a scare to win through to the third round of the Australian Open on a mixed day for the women's seeds at Melbourne Park.
As well as Kvitova, the other seeds to go through on Thursday have been Russian No.4 seed Maria Sharapova, her seventh-seeded compatriot Vera Zvonareva, American No.12 seed and five-time winner Serena Williams, 21st-seeded Serbian Ana Ivanovic and German No.30 seed Angelique Kerber.
But there have been four casualties as well, with Russian 15th seed Anastasia Pavlyuchenkova headlining a group that also includes Italian No.23 Roberta Vinci, Estonian 25th seed Kaia Kanepi and Pavlyuchenkova's 29th-seeded countrywoman Nadia Petrova.
After cruising through her opening-round encounter against Russian Vera Dushevina on Tuesday, Czech No.2 seed Kvitova looked headed for another comfortable outing when she took the first set against Spaniard Carla Suarez Navarro.
But having saved the only break point she faced in the first set, Kvitova gave up her serve twice in the second from two chances as Suarez Navarro fought back to force a deciding set and then broke again in the first game.
A quarter-finalist at Melbourne Park 12 months ago, Kvitova retrieved the break immediately though and then went back-to-back in the fifth game as she finished stronger to set up a shot at either Russian 27th seed Maria Kirilenko or Canadian Aleksandra Wozniak with the 6-2 2-6 6-4 win.
A triple Grand Slam winner, including her 2008 Australian Open triumph, Sharapova has started her campaign with two ruthless displays, the latest a 6-0 6-1 demolition of American Julie Hampton.
Sharapova, who hasn't been beyond the fourth round at Melbourne Park since she won the title, will now be doing her homework on Kerber after she ousted Frenchwoman Stephanie Dubois 7-5 6-1.
Zvonareva, who has been to the semi-finals twice in the past three Australian Opens, looked set to win quickly as well when she won the first set against Czech Lucie Hradecka in only 32 minutes but she had to work harder before prevailing 6-1 7-6 (7-3).
Next up she'll face compatriot Ekaterina Makarova, who committed no unforced errors as she rolled Kanepi 6-2 7-5 in a match that featured just two winners each, Makarova's ability to take her chances with seven breaks to four the major difference.
Williams, who won the title at Melbourne Park in 2003, '05, '07, '09 and 2010, seemed headed for a quick kill when she took the first set in only 22 minutes against Czech Barbora Zahlavova Strycova.
But the 13-time major winner faced a stronger challenge in the second set before breaking for a fifth time in the 10th game to seal the 6-0 6-4 win and set up a match against either Slovakian 17th seed Dominika Cibulkova or Hungarian Greta Arn.
A dual Australian Open junior champion, including in 2006 when she beat current world No.1 Caroline Wozniacki, Pavlyuchenkova started well against American Vania King but faded as the match went on, with King winning 5-7 6-3 6-4 to reach the third round here for the first time.
Ivanovic, who was beaten in the decider four years ago by Sharapova before claiming her maiden major title just months later at Roland Garros, completed her easy 6-2 6-3 victory over Dutchwoman Michaella Krajicek at Hisense Arena just seconds before Sharapova.
Apart from 2008, Ivanovic has had a largely forgettable experience in her seven previous visits