Defending champion Iga Swiatek escaped from match point down against Naomi Osaka to reach the French Open third round on Wednesday, while Carlos Alcaraz overcame a scare of his own as persistent rain caused widespread disruption to the tournament.

Swiatek outlasted fellow four-time Grand Slam winner Osaka 7-6 [7/1], 1-6, 7-5 in a breathtaking second-round clash, livening a gloomy day in which 23 singles matches were postponed until Thursday.

World number one Swiatek won the last five games of the match to keep her bid for a third successive Roland Garros title on track. Justine Henin was the last woman to achieve the feat in 2005-07.

Osaka, appearing at only a second Grand Slam since giving birth to her daughter last July, was on the cusp of her biggest win since returning to tennis at the start of the year but took a philosophical view to an agonising defeat.

Three break points eluded Swiatek to start the deciding set and Osaka's clean hitting quickly had her opponent again on the back foot.

Osaka blasted a backhand winner to break for a 2-0 advantage before demonstrating her resolve once more to save another five break points.

Swiatek fended off a break opportunity to stay in touch at 2-4, but she looked doomed when Osaka brought up match point three games later.

A terrific return kept her alive and a loose backhand from Osaka handed Swiatek a break to get back to 4-5.

After a tough hold, Swiatek broke again to move 6-5 in front before holding her nerve to wrap up victory after nearly three hours.

US Open champion and third seed Coco Gauff defeated Slovenia's Tamara Zidansek 6-3, 6-4, while eighth seed Ons Jabeur overcame Colombia's Camila Osorio in three sets.

Alcaraz shook off a third-set blip against world number 176 Jesper de Jong before the Spaniard came through 6-3, 6-4, 2-6, 6-2 under the roof on Court Philippe Chatrier.

Other winners in the men's draw were Second seed Jannik Sinner, Sixth seed Andrey Rublev and former French Open finalist Stefanos Tsitsipas. (AFP)