Petra Kvitova made a surprise second-round exit at the Australian Open on Wednesday. (More Tennis News)
The Czech ninth seed and two-time Wimbledon champion fell to Sorana Cirstea 6-4 1-6 6-1 on a warm day at Melbourne Park.
Runner-up in 2019 and a quarter-finalist last year, Kvitova bowed out after a costly 44 unforced errors in two hours, three minutes.
Cirstea, meanwhile, reached the third round of the Australian Open for just the fourth time.
It marked the Romanian's first win over a top-10 player since 2017, when she beat Karolina Pliskova in Beijing.
Cirstea will face another Czech, 19th seed Marketa Vondrousova, in the third round.
Kvitova is among 10 seeds to have departed in the women's draw, joining Victoria Azarenka, Angelique Kerber, Bianca Andreescu, Petra Martic, Johanna Konta, Maria Sakkari, Wang Qiang, Zhang Shuai and Alison Riske.
