Gracheva closed out a hard-fought 7-5, 6-3 victory and joined in the singing as she celebrated being the last Frenchwoman left in the women's draw.
"I will remember this moment until the end of my life," said Gracheva, who received her French passport in 2023 after living in the country for more than five years. "It means that everyone accepts me, that I'm home here."
Ranked 39 at the start of the year, her best career ranking, Gracheva fell to 100th place in April after six consecutive tournaments where she was eliminated in the first round.
"At the start of the year I was in some despair, I was very frustrated," she said. "If someone had told me that I would be playing on the Suzanne Lenglen I wouldn't have believed it," she said with a big smile.
Gracheva, ranked 88 and who has never won a tournament, beat sixth-ranked Maria Sakkari in the first round.
She will face 38th-ranked Russian Mirra Andreeva or 62nd-ranked American Peyton Stearns in what will be her first fourth round of a Grand Slam tournament.
"I'm just happy to be here, if I can go even further, that's a bonus. I'm proud," she said.
