World number one Naomi Osaka was forced to withdraw from the Italian Open due to a hand injury.
The 21-year-old from Japan pulled out before her scheduled quarter-final against Holland's Kiki Bertens, citing a problem with her thumb.
Bertens will face Johanna Konta in the semi-finals in Rome after the British number one beat Czech teenager Marketa Vondrousova in her quarter-final.
Osaka said she was unable to grip her racket properly after winning both her matches in straight-sets on Thursday.
Wednesday's rain forced the players to play two matches in a day and Osaka beat both Slovakia's Dominika Cibulkova and Romania's Mihaela Buzarnescu in straight sets.
"I woke up (on Friday) morning and couldn't really move my thumb," Osaka told a press conference.
"I tried to practice and grip my racket, but I couldn't and then I kept feeling this pain whenever I tried to move my hand in different directions.
"Right now, I'm really, not mad, but in between sad and disappointed because I really wanted to play my match."
Konta, who beat Sloane Stephens and Venus Williams on Thursday, maintained her best run at a premier tournament on clay, by overcoming Vondrousova 6-3 3-6 6-1.
Czech Karolina Pliskova won through to the last four with a 6-7(5) 6-2 6-2 victory over another former world number one Victoria Azarenka, of Belarus.
Fourth seed Pliskova will face Maria Sakkari in the other semi-final after the 23-year-old Greek beat France's Kristina Mladenovic 5-7 6-3 6-0.
