Defending champion Iga Swiatek reached the quarterfinals after beating unseeded 18-year-old Marta Kostyuk of Ukraine 6-3, 6-4 in the fourth round.
Kostyuk saved one match point on her second serve at 30-40 as she held in the ninth game of the second set.
That forced Swiatek to serve out the match and she clinched victory with a smart lob from the net.
Swiatek has now won 22 straight sets at Roland Garros, including her run to the title last year.
She next faces 17th-seeded Greek Maria Sakkari, who reached her first Grand Slam quarterfinal.
Swiatek is also in the last eight of the women's doubles.
Kostyuk reached the third round of the Australian Open at the age of 15 on her Grand Slam debut — the youngest to go that far in 21 years — but this was her best run at any major.
