ADELAIDE, Australia -- Wimbledon champion Marketa Vondrousova withdrew from the Adelaide International on Tuesday citing a right hip injury, five days before the Australian Open starts in Melbourne.

The No. 7-ranked Vondrousova pulled out of the tournament hours before her scheduled first-round match against Russian qualifier Aliaksandra Sasnovich.

Taylor Townsend will take her place in the draw.

Sixth-seeded Jelena Ostapenko was broken while serving for the match at 5-2 in the third set and missed two match points in the next game before finally fending off Sorana Cirstea 2-6, 6-2, 6-4.

The 2017 French Open champion will next play Caroline Garcia, who beat local wildcard entry Taylah Preston, Australia, 6-4, 1-6, 6-3.

"I feel like I was sleeping in the first set," Ostapenko said. "I'm not a morning person; I needed time to get into the match. When I start to take time and be a bit more calm, I play better."

Czech qualifier Katerina Siniakova upset former No. 1-ranked Karolina Pliskova 6-2, 6-1, winning 10 consecutive games after dropping serve early.

Two days after helping Germany win the United Cup final, Laura Siegemund needed almost three hours for her 6-7 (1), 6-4, 6-4 win over seventh-seeded Liudmila Samsonova, recovering breaks in the second and third sets.

In the ATP tournament in Adelaide, Australia's Jordan Thompson followed up his win over Rafael Nadal last week in the Brisbane International quarterfinals with a 6-2, 6-2 over Facundo Diaz Acosta to move into second-round match against No. 4-seeded Lorenzo Musetti.

Hobart InternationalSloane Stephens, the 2017 US Open champion, was broken while serving for the match and then lost 6-4, 3-6, 7-6 (5) to No. 73-ranked Chinese qualifier Yuan Yue. Stephens was coming off a second-round exit last week at the Brisbane International, her first tournament since September.

Also in Hobart, sixth-seeded Sofia Kenin, who won the Australian Open and reached the French Open final in 2020, opened with a 6-3, 6-3 win over Greet Minnen.

No. 9-seeded Tatjana Maria was leading 6-1, 4-3 when Nadia Podoroska retired from their match.