Gold medal favourite Iga Swiatek begun her Olympic campaign with a testing victory over Irina-Camelia Begu in Paris.
Polish world number one Swiatek has won the past three French Open titles at Roland Garros and is almost untouchable on clay.
But she had to fight hard in a tight second set to see off the Romanian 6-2 7-5.
Swiatek, who has won 22 matches in a row at Roland Garros, will face either Nadia Podoroska or Diane Parry in the second round.
Italy’s Jasmine Paolini, runner-up to Swiatek in the French Open showpiece in June, also advanced with a 7-5 6-3 win over Ana Bogdan of Romania.
Swiatek has spoken this year of wanting to win Olympic gold, boosted by the fact it is held on her favourite surface.
Four of her five Grand Slam titles have come on the Paris clay and she is a formidable frontrunner in a match.
However, she had to work hard against Begu, going a break down in the second set with her forehand and serve misfiring.
Begu served to force a decider at 5-4 but nerves played a part, with Swiatek breaking back and winning the match on a Begu double fault.
The match was played under the roof on Court Philippe-Chatrier, with the first day’s play heavily disrupted by rain.
No play has been possible on the outside courts, where Britons Jack Draper, Cameron Norrie, Dan Evans and Katie Boulter are due to begin their singles campaigns.
