Tenth seed Victoria Azarenka suffered a shock straight-sets defeat by world number 161 Anna Karolina Schmiedlova in the French Open second round.
The Belarusian, 31, reached the US Open final earlier this month but struggled on the clay against Schmiedlova, who won 6-2 6-2.
The Slovak fell in the second set and the trainer was needed to treat her knee, but it did not halt her progress.
Earlier, third seedElina Svitolinabeat Mexican qualifier Renata Zarazua.
The Ukrainian, 26, failed to win a game in the second set but recovered to claim a 6-3 0-6 6-2 victory.
“I was trying to get back into the match,” she said. “I lost my way a bit and was making too many errors.”
- Follow day four of the French Open
- French Open 2020: Heather Watson concerned about future of British tennis
Svitolina won her 15th WTA title in Strasbourg last week but is yet to reach a Grand Slam final.
She will face Russian world number 31 Ekaterina Alexandrova next.
A possible meeting with Serena Williams in the quarter-finals is no longer on the cards after the American 23-time Grand Slam championwithdrew before her second-round matchwith an Achilles injury.
- How Do You Cope?:Fabrice Muamba on the night that changed his life
- Football Daily:All the reaction from some heavyweight EFL Cup ties