Former US Open champion Sloane Stephens showed why she is one of the French Open's most dangerous unseeded players by knocking out Karolina Pliskova.
American Stephens won what had been an eye-catching first-round encounter 6-0 6-4 against the Czech 16th seed and two-time Grand Slam finalist.
Stephens, runner-up in Paris in 2018, was not ranked high enough to be seeded when the draw was made last week but is now 30th, which would have been enough.
Compatriot Madison Keys also advanced.
Keys, beaten by Stephens in the 2017 US Open final, won 6-1 3-6 6-1 against Estonia's Kaia Kanepi, while 2021 runner-up Anastasia Pavlyuchenkova of Russia beat Czech teenager Linda Fruhvirtova 6-2 6-2.
Later on Monday, French fifth seed Carolina Garcia opens her campaign against China's Wang Xiyu, while two-time Wimbledon champion Petra Kvitova and Elina Svitolina are also in action.