World No. 6 Marketa Vondrousova suffered an injury setback less than two weeks before her Wimbledon title defense when she was forced to retire from her Berlin Ladies Open second-round match against Anna Kalinskaya on Thursday.
The 24-year-old Czech player was leading 5-3 in the opening set before she slipped and retired at 5-5 with what appeared to be a hip problem.
Kalinskaya, ranked 24th, will face Aryna Sabalenka in the quarterfinals after the two-time Grand Slam champion defeated Daria Kasatkina 6-1, 6-4.
It was a good day for 2022 Wimbledon champion Elena Rybakina, as she beat Veronika Kudermetova 6-4, 7-5. Other top-ranked players, including Coco Gauff, Jessica Pegula and Ons Jabeur, also advanced.
Wimbledon runs from July 1-14.