The 39-year-old Williams, a three-time champion in Paris, won 6-3, 5-7, 6-1 and will face fellow American Danielle Collins for a place in the last 16.

Williams, seeded seventh, has been one short of Margaret Court's all-time record of 24 majors since winning the Australian Open in 2017.

              
Bencic knocked out by Kasatkina                 
                  
In the women's draw, Swiss 10th seed Belinda Bencic failed to improve her poor French Open record as she lost 6-2, 6-2 to Russia's Daria Kasatkina.

Bencic has still never made the fourth round in five appearances.

Former world number one Victoria Azarenka set up a third-round tie against Madison Keys with a 7-5, 6-4 win over Denmark's Clara Tauson.

The Belarusian's best Roland Garros run was a semi-final appearance eight years ago and this is the first time she has made round three since 2015.

The United States' Keys, who lost to Sloane Stephens in the 2018 last four, saw off Canadian teenager Leylah Fernandez 6-1, 7-5.