Former world number one Viktoria Azarenka became the only player to reach the semi-finals of the Berlin grass court tournnament on a wet Friday, when opponent Elena Rybakina retired early in the first set due to illness.
Azarenka was 3-1 up when 2022 Wimbledon champion Rybakina left the court and did not return. Organizers said she suffered from "extreme abdominal pain."
Jessica Pegula was 4-2 up against Katerina Siniakova when rain stopped play for the day.
The match is to be completed on Saturday, with the remaining quarter-finals Coco Gauff v Ons Jabeur and Aryna Sabalenka v Anna Kalinskaya also moved.
It will be a busy day, with the semis also set for Saturday in the tune-up for Wimbledon which starts on July 1.