Former world number one Venus Williams followed her sister Serena out of the French Open, losing 6-2 6-3 to third seed Agnieszka Radwanska in round two.
Unseeded Venus, the seven-time Grand Slam winner now ranked 53 following illness, was beaten in exactly an hour.
Top seed Victoria Azarenka eased through with a 6-1 6-1 victory over Germany's Dinah Pfizenmaier.
Eighth seed Marion Bartoli served 14 double faults as she surprisingly lost 6-2 3-6 6-3 to Croatia's Petra Martic.
Venus, who began the year at 134 in the world rankings after being diagnosed with Sjogren's Syndrome, a fatigue-inducing autoimmune disease, has never won the French Open. Her best effort came in 2002 when she lost in the final to her sister.
The 31-year-old was never able to trouble Radwanska on Court Phillipe Chartrier, the scene of Serena's shock three-set defeat against Virginie Razzano 24 hours earlier.
She lost her opening service game and Radwanska, who has won three titles this year, secured the first set with an ace after 28 minutes.
The 23-year-old Polish player, who has yet to progress beyond the quarter-final stage in a Grand Slam event, combined outstanding fitness with some flawless strokeplay.
In the next round she will play 2009 champion Svetlana Kuznetsova, who needed a second set tie-break to overcome Yung-Jan Chan in an hour and 41 minutes.
US Open winner Sam Stosur beat American Irina Falconi 6-1 6-4 and next faces 27th seed Nadia Petrova of Russia.
Stosur, who lost the 2010 French Open final to Francesca Schiavone, has dropped only nine games in her first two matches this year.
The 28-year-old Australian again looked comfortable against Falconi, ranked 112, who was appearing in the second round for the first time.
Azarenka, who lost the first set and was a point away from a 5-0 deficit in the second against world number 105 Alberta Brianti in the opening round, needed only 55 minutes to dispatch Pfizenmaier, who is currently ranked 198th.
The Belarusian is seeking to become the first woman since Jennifer Capriati in 2001 to win the first two Grand Slams of the season, having won the Australian Open in January.
She lost the first game but proceeded to win the next 11 in succession against her 20-year-old opponent, who made 29 unforced errors.
In round three Azarenka will play Aleksandra Wozniak of Canada, who beat 31st seed Zheng Jie of China 6-2 6-4.
Bartoli, a semi-finalist last year, came from a break down in the second set to level at one set apiece against world number 50 Martic but never looked comfortable under threatening skies on Court Suzanne Lenglen.
Martic, 21, served an ace on her second match point to complete victory in two hours and 12 minutes, setting up a third-round meeting with 29th seed Anabel Medina Garrigues of Spain.
Fifteenth seed Dominika Cibulkova of Slovakia quickly advanced with a 6-0 6-2 victory over American Vania King.
Cibulkova will meet Maria Jose Martinez Sanchez for a place in the last 16 after the Spaniard beat 20th seed Lucie Safarova of the Czech Republic 6-4 7-5.
Italian Sara Errani, the 21st seed, beat Melanie Oudin of the USA 6-2 6-3 and now plays the 2008 champion Ana Ivanovic, this year's 13th seed, who beat Shahar Peer of Israel 6-2 6-2.
Former world number one Ivanovic, 24, has failed to reach the quarter-finals at Roland Garros in the last three years.
She has a favourable-looking draw through to the last eight this time, where she could face Radwanska.