The No. 12 seed, Daniil Medvedev, also lost, wasting a two-set lead to Pierre-Hugues Herbert of France and falling, 4-6, 4-6, 6-3, 6-2, 7-5. Juan Ignacio Londero upset No. 15 Nikoloz Basilashvili, 6-4, 6-1, 6-3.
In the women’s draw, No. 18-seeded Julia Görges of Germany was beaten, 7-5, 6-1, by Kaia Kanepi of Estonia. Other winners included No. 4 Kiki Bertens, No. 8 Ashleigh Barty and No. 26 Johanna Konta.
Rafael Nadal, Novak Djokovic and Serena Williams — owners of a combined total of 55 major championships — were scheduled to play, one after another, on the main Philippe Chatrier court.
Nadal, the 11-time champion at Roland Garros, has made light work of the qualifier Yannick Hanfmann, winning, 6-2, 6-1, 6-3 to advance to the second round. Nadal saved four break points in his first service game but was never troubled again by the 184th-ranked German, who was playing for the first time in the French Open main draw.
Wozniacki’s preparation for Paris had been hampered by an injured left calf, which was heavily wrapped Monday, but she said that was not an issue against Kudermetova, 22. Wozniacki also said she was not bothered by her rheumatoid arthritis, an autoimmune condition that can cause pain and swelling in the wrist and other joints.
“I played really well in the first set,” Wozniacki said, her chin resting on her left hand. “I played aggressive. I played the way I wanted to play. And then I think she got very lucky at the start of the second set and took advantage of the opportunities she got. And then I think I just lost a little steam in the end.”
She made only three unforced errors in that opening set, but 18 over the last two.
Wozniacki’s results have not been the sort she is accustomed to. She made it to the quarterfinals and the fourth round in Paris in the last two years.
“You want to win, you’re competitive, you work hard and you want to see results,” she said. “So, it hasn’t been a great year for me so far. And I’m just going to try and work hard and try to turn that around. Right now, there’s not much I can do about the first six months of the season. I had some good weeks where I felt great, and then I’ve had some weeks where I’ve been sick and some weeks where I’ve been injured.”