Paris/UNI: Top seed Iga Swiatek dispatched Spaniard Cristina Bucsa 6-4, 6-0, setting up a second-round clash against American No. 102 Claire Liu.
American sixth seed Coco Gauff, the 2022 Roland Garros finalist, rallied from a set down to overcome Spain's Rebeka Masarova 3-6, 6-1, 6-2, avoiding an early exit.
Wimbledon champion Elena Rybakina of Kazakhstan triumphed 6-4, 6-2 over Brenda Fruhvirtova of the Czech Republic.
Earlier in the day, last year's men's finalist Casper Ruud returned to Paris in winning style. The Norwegian advanced to the clay-court major's second round for the sixth successive season, defeating Swedish qualifier Elias Ymer in straight sets, 6-4, 6-3, 6-2.
The fourth seed struck 28 winners against 17 from his No. 155-ranked opponent, concluding the victory in two hours and seven minutes on Court Suzanne-Lenglen.
"It was tough. First match after one of the best tournaments of my life," Ruud admitted. "Obviously I'm a bit nervous. You have to defend what you did last year," said Ruud, who lost to Rafael Nadal in the final 12 months ago.
The 24-year-old is aiming for his maiden Grand Slam title after two consecutive final appearances last year, one at Roland Garros and another at the US Open where he was narrowly defeated by Spaniard Carlos Alcaraz.
Ruud claimed his 10th Tour-level trophy in Estoril in April and reached the semifinals in Rome before coming to Roland Garros. His next opponent will be another qualifier, Giulio Zeppieri of Italy, who defeated Kazakhstan's Alexander Bublik to advance.
Germany's Alexander Zverev, who sustained a serious ankle injury during the semifinals here last year, celebrated a triumphant return. The two-time French Open semifinalist won two tiebreaks to defeat South African Lloyd Harris 7-6(6), 7-6(0), 6-1, advancing to the second round.
The 26-year-old was wheeled off the court during his semifinal match against Nadal last year and was sidelined for six months with torn ligaments.
"It's very, very nice to be back," Zverev expressed on the court. The 22nd seed will confront Slovakia's Alex Molcan next.