Anastasia Potapova retired from her Berlin Open first-round match against Ekaterina Alexandrova after losing the opening set 6-1. The 25-year-old cited a neck injury and ongoing illness for the withdrawal.
Potapova avoided a post-match hug from Alexandrova at the net and offered a handshake instead. She later explained the decision was to avoid passing on her virus.
The incident followed a similar retirement the previous week at the Libema Open due to illness. Potapova had started the Berlin match strongly but could not continue.
She remains entered in doubles alongside Diana Shnaider. Their match against Jessica Pegula and Coco Gauff was scheduled for Monday, though her participation is now uncertain.
Potapova reached the French Open round of 16 earlier this season and climbed to a ranking of No. 26.