By Martyn Herman
PARIS (Reuters) - Heavy rain from depressing grey skies kept the players off court and the fans huddled under umbrellas at the French Open on Thursday as only five matches were completed by mid-afternoon.
The action began on time but a near two-hour interruption, followed by a short dry period, and then yet more rain threatened to play havoc with the schedule for the second time in the tournament.
Former women's runner-up Samantha Stosur took advantage of the two periods of play to reach the third round with a 6-4 6-3 defeat of Frenchwoman Kristina Mladenovic on center court.
The Australian next faces 18th seed Jelena Jankovic in a repeat of their 2010 semi-final after the Serbian won 12 successive games to beat Spain's Garbine Muguruza 6-3 6-0.
Kazakh Yaroslava Shvedova became the day's first seed to fall, the 27th seed losing to Argentina's Paula Ormaechea.
If the rain relents both the men's and women's champions are due on court later with Rafa Nadal up against Martin Klizan and Maria Sharapova playing Eugenie Bouchard of Canada.
Earlier Taiwan's Lu Yen-Hsun had to withdraw from the tournament with an ankle injury before he took to court to face 16th seed Philipp Kohlschreiber.
Victor Hanescu of Romania also benefitted from another player's ill-fortune when his second-round opponent Dmitry Tursunov was forced to retire trailing 6-4 6-6.
Tournament organizers managed to get the schedule back on track on Wednesday after 11 matches were cancelled by rain on Tuesday. The third round is supposed to start on Friday.
Play was unlikely to start before 1530 local time.
(Editing by Justin Palmer)