Naomi Osaka was forced to retire from the first grass-court final of her career Saturday, two days before the start of Wimbledon.

The four-time Grand Slam champion appeared to turn her right ankle early in the first set of her match against Czech world No. 11 Karolína Muchová, at the Bad Homburg Open in Germany. Despite playing on after a trainer visit, Osaka lost the set 6-1.

After a lengthy game to open the second set — in which Muchová held serve — Osaka had a brief conversation with her box, including coach Tomasz Wiktorowski, as she prepared to switch ends. At the end of the discussion, Osaka decided not to continue. She walked across the court to Muchová and shook hands while explaining the situation.

“I apologize for not being able to finish, but this atmosphere was incredible throughout the whole week, so thank you so much, and I hope you’re not too hot,” she said in her on-court interview.

Osaka, 28, had been in fine form in Germany, beating world No. 26 Elise Mertens, world No. 19 Ekaterina Alexandrova and Wang Xinyu, who last year reached the final of the Berlin Tennis Open, another Wimbledon warm-up event played on grass.

However, Osaka’s injury comes at a bad time ahead of her opening match at the All England Club, scheduled for Monday against Elsa Jacquemot of France on No. 3 Court.

Osaka’s early exit from her match is the latest of three during the run-up to the third Grand Slam of the year.

Jelena Ostapenko of Latvia and Petra Marčinko of Croatia both retired from their semifinals at the Eastbourne Open in England.

Ostapenko withdrew while down a set (6-1) to 2025 Queen’s champion Tatjana Maria. A tournament doctor checked Ostapenko’s blood pressure midway through her first set.

Marčinko pulled out of her match against 2025 Australian Open champion Madison Keys after losing the first 6-1. Marčinko cited an abdominal injury.

Osaka’s withdrawal gives Muchová, 29, her first title on grass, her second of 2026 and the third of her career. She will face Russia’s Anastasia Zakharova in the first round of Wimbledon, also on Monday.