Britain's Heather Watson beat Nicole Gibbs 5-7 6-2 6-2 in her rain-delayed match to book her place in the second round of the French Open in Paris.
Gibbs was serving at 2-1 up in the third set when the players were called off on Sunday because of heavy rain.
Following a further rain delay on Monday, Watson twice broke the American's serve as she won four games in a row to seal an impressive victory.
Compatriots Andy Murray, Kyle Edmund and Naomi Broady are in action later.
Murray takes on 37-year-old Czech Radek Stepanek, Edmund faces qualifier Nikoloz Basilashvili, while Broady is scheduled to play American Coco Vandeweghe.