Williams will face Julia Goerges or Alison Van Uytvanck in the third round.
Serena Williams beat No. 17 seed Ashleigh Barty in the second round of the French Open on Thursday.
She won 3–6, 6–3, 6–4 to advance to the third round.
Williams dropped the first set to Barty 6–3. Williams mounted a comeback in the second set by taking a four games to one lead before winning the set 6–3.
The 36-year-old unseeded Williams then took a 3–1 lead in the deciding final set to win 6–4.
On Tuesday, Williams won her first Gland Slam match following the birth of her daughter in September, beating Kristyna Pliskova in straight sets. She hadn't had a Grand Slam victory since she won the 2017 Australian Open.
Williams is seeking her 24th Grand Slam title at Roland-Garros. She will face Julia Goerges or Alison Van Uytvanck in the third round.