Iga Swiatek (22) pulled out of the Bad Homburg Open ahead of her semi-final match on Friday after the world number one said she had come down with fever and possible food poisoning.
Swiatek was set to play Lucia Bronzetti (24) in the semi-finals of the grass-court tournament, a tune-up event for Wimbledon which begins on Monday.
"I'm so sorry but I have to pull out of my match today. I had a restless night because of some fever and possible food poisoning," Swiatek wrote on Twitter.
"I'm not able to perform today and I need to take care of myself. I hope I'll be fine soon. Your support in Bad Homburg was amazing, thank you."
Swiatek, who has never moved past the fourth round at Wimbledon, begins her quest for a maiden grass-court title at the All England Club against China's Zhu Lin (29) in the first round.
Wimbledon runs from July 3rd-16th.
