Six-times Grand Slam champion Iga Swiatek retired from her Madrid Open round-of-32 match against American Ann Li on Saturday due to illness, trailing 6-7(4) 6-2 0-3.
The fourth seed at the WTA 1000 clay-court tournament left the court in tears, having called for medical assistance during the match.
"The past two days were pretty terrible, I think I have some virus," said Swiatek, who won the Madrid title in 2024.
"It's been some hours fine, some hours pretty bad. I had zero energy, zero stability, and I just felt really bad physically.
"I knew that (it was) going to be hard but I still wanted to try because I already have been sick twice in my career and I could still win most of my matches. I guess it depends on how bad it is, and I guess this time it was worse than before."
Swiatek's withdrawal deals a blow to her preparations for the French Open, a tournament the Pole has dominated in recent years, winning the title four times, most recently in 2024.
Swiatek, 24, is expected to continue her build-up to Roland Garros at the Italian Open, which runs from May 5-17.
The French Open main draw gets underway on May 24.

Iran wait on World Cup progress after draw with Egypt
Belgium beat New Zealand 5-1 to advance to World Cup knockout stage
Baena strike sends Spain past Uruguay into World Cup knockouts
Jubilant Cape Verde set date with Argentina in World Cup round of 32
Senegal ring up 5-0 win over 10-man Iraq, keep knockout hopes alive
