Wimbledon champion Petra Kvitova was on court only for 38 minutes in her third-round match Saturday before advancing at the Australian Open.
The second-seeded Czech was leading 6-0, 1-0 on Rod Laver Arena when Maria Kirilenko retired with a left thigh injury. The Russian had treatment for the injury in the first set and, after dropping serve immediately in the second, she walked to the net and shook hands with Kvitova.
It was the fourth retirement of the women's tournament.
Kvitova, one of four players who could end the season's first major with the top ranking, will face Ana Ivanovic of Serbia or unseeded American Vania King in the Round of 16.