World No. 4 Karolina Pliskova fought off a first-round challenge from qualifier Mayar Sherif of Egypt to advance at the French Open on Tuesday.

The second-seeded Pliskova wasn't too happy with her performance following the 6-7 (9), 6-2, 6-4 win at a cold and rainy Roland Garros in Paris.

"Let's not talk about my level," Pliskova said following the match. "I think there is big room for improvement, but it is what it is and I'm in the next round, which counts."

Pliskova entered the tournament a week after being forced to retire in the final of the Internazionali BNL d'Italia title because of a thigh injury.

"I was not really thinking about it at all," the former World No. 1 said about the left-thigh issue. "It's not 100 percent, but it's OK. I think nobody is really 100 percent here."

Also advancing after being pushed to three sets was No. 4 Sofia Kenin, who topped Russian Ludmilla Samsonova 6-4, 3-6, 6-3.

The two had to contend with a rain delay between the first two sets that lasted nearly two hours.

Kenin, the reigning Australian Open champion, benefited from 11 double faults from her opponent. Neither woman served well, with Kenin capitalizing on six of 13 break chances while Samsonova broke Kenin's serve five times.

Still, Kenin was satisfied.

"Conditions weren't the best. It was really tough with the courts, and it was raining and we went inside and then it started raining again," she said. "Yeah, conditions weren't easy at all, but I'm just happy with the way I competed and found a way to win.

"I didn't feel like I was playing my best tennis, but of course she was playing really well, but I'm just happy to have gone through the first round."

Sloane Stephens, a finalist in Paris in 2018, had a much easier first-round match, eliminating Russia's Vitalia Diatchenko 6-2, 6-2 in their first-ever meeting.

Two other Americans were ousted, however.

Julia Goerges of Germany upended Alison Riske, the 19th seed, 6-3, 6-7 (4), 6-1, while 17-year-old Clara Tauson of Denmark defeated 21st seed Jennifer Brady 6-4, 3-6, 9-7 in a two-hour, 45-minute meeting.

Tauson, a qualifier, was playing in just her second match on the tour and fought off two match points on her way to the win.

"We played an amazing match today, probably the highest-quality tennis I've ever played in my life," Tauson told rolandgarros.com.

"I was just grateful to be there and just happy that I could play a girl like her on a big court. It was a dream come true, of course, and then winning the match, I don't have any words yet. It was so great, I've never really experienced a match like that.".

Also winning was No. 14 seed Elena Rybakina of Kazakhstan, who defeated Sorana Cirstea of Romania 6-0, 6-3.