American sixth seed Coco Gauff and Tunisian seventh seed Ons Jabeur put a recent lack of form behind them to reach the French Open second round.
Gauff, who reached the final at Roland Garros last year, fought back from behind to win 3-6 6-1 6-2 against Spain's Rebeka Masarova.
Jabeur, whose preparations were disrupted by a calf injury, won 6-4 6-1 against Italy's Lucia Bronzetti.
Jabeur won in little over an hour as she avoided another early Paris exit.
Last year she was beaten in the first round on the Roland Garros clay but avoided the same fate by making strong starts to both sets against 65th-ranked Bronzetti.