Slovakia duo Dominika Cibulkova and Daniela Hantuchova pulled out of their respective matches at the Qatar Open on Tuesday.
Australian Open finalist Cibulkova was struck down with a stomach bug and retired early in her match against Alisa Kleybanova.
"I was really looking forward to playing this week in Doha," a disappointed Cibulkova told reporters. "Unfortunately I became very sick today and suddenly did not feel well. I wanted to give it a try today and I did everything I could to play, but I could not continue."
World number 30 Hantuchova suffered a knee injury and quit shortly after losing the first set 7-5 in her first-round clash with Ana Ivanovic.