Krystina Pliskova, who shared the Wimbledon winners' stage with Serena back in 2010 - the Czech was junior champion as Serena won the real thing that year, played her part across the net on centre court, but there was only one star.
Dressed in a skintight, all-in-one black bodysuit, broken up by a vivid scarlet belt, Serena captivated the French crowd from the start of the contest to its 7-6(4) 6-4 conclusion.
"Two years has been a really long time," Williams told the crowd in French, referring to her last match on clay.
"I am just so happy to have won a match here... thank you all."
The last time Williams had appeared in a Grand Slam tournament was at the Australian Open in 2017, when she won it while pregnant with daughter Alexis Olympia.
The 36-year-old superstar was controversially overlooked for a seeding in Paris and has slipped to No.453 in the world.
Next up for Williams is a clash against Australian 17th seed Barty.
Australia's no.1 ranked woman produced a thumping 6-3 6-1 victory over Russian Natalia Vikhlyantseva.
Showing no signs of the back problem that had her in doubt for the clay-court grand slam, Barty blasted past the world No.81 in just 64 minutes.
