Anhelina Kalinina progressed to round two of the Transylvania Open after opponent Eugenie Bouchard retired injured in Cluj.
Ukrainian world number 45 Kalinina took the opening set 6-3 before a hip injury prevented Bouchard from continuing.
The Canadian revealed she had retired as a precaution having undergone an MRI on Monday, and did not wish to aggravate the issue any further.
“I’m just disappointed to have ended my tournament in Romania this way because I really loved being here in Cluj,” she said. “I pulled my hip flexor a few days in practice. I tried everything to be ready for this match.
“I got an MRI yesterday, and didn’t show anything too bad, so I thought I could play. But it was getting worse as the match went on. To avoid a big injury, I figured it would be best to retire.
“I absolutely hate retiring, I wish I could’ve done better here, but I hope to be back.”
Fourth seed Anastasia Potapova beat Ann Li 6-2 7-6 (7-5) to set up a clash with Viktorija Golubic, who overcame Diane Parry in straight sets.
Seventh seed Xiyu Wang advanced in straight sets against home favourite Jaqueline Cristian, while Harriet Dart required just 64 minutes to wrap up a commanding 6-2 6-0 victory over Oceane Dodin.