Defending champion Iga Swiatek staged a remarkable comeback from match point down against Naomi Osaka to advance to the French Open third round on Wednesday.

Meanwhile, Carlos Alcaraz also faced a tough challenge but managed to secure victory amid persistent rain that disrupted the tournament schedule.

In a thrilling second-round encounter, Swiatek outlasted four-time Grand Slam winner Osaka with a score of 7-6 (7-1), 1-6, 7-5. Her victory brightened a gloomy day that saw 23 singles matches postponed until Thursday.

The world No. 1 rallied in the final moments of the match, winning the last five games to keep her quest for a third consecutive Roland Garros title alive. The last woman to achieve this feat was Justine Henin from 2005 to 2007.

Swiatek aims to become only the fourth woman in the Open era to win four Roland Garros titles and the second, after Serena Williams, to complete the clay-court treble of Madrid, Rome and the French Open in the same season.

"This match was really intense, much more intense for the second round than I ever expected," said Swiatek, who fought off a break point on Osaka's serve while trailing 5-3 in the deciding set.

"Naomi played amazing tennis, and maybe she is going to be a clay-court specialist in a while!"

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 of an agonizing defeat.

"I cried when I got off the court, but then, you know, for me, I kind of realize I was watching Iga win this tournament last year, and I was pregnant. It was just my dream to be able to play her," said Osaka, now ranked 134.

Entering the showdown with a 29-2 record in Paris, Swiatek landed the initial blow in the first meeting on clay between past and present world No. 1s, breaking Osaka to love for a 2-1 lead.

Osaka, who won a match at a Grand Slam event for the first time since the 2022 Australian Open with her opening victory over Lucia Bronzetti, clawed back to 4-4 as Swiatek miscued a forehand following a lengthy rally.

The Japanese star had Swiatek in trouble down set point on the Pole's serve in the 10th game, but the top seed knuckled down and forced a tie-break, which she dominated to snatch the opening set after 69 minutes.

Osaka produced a stirring response and broke Swiatek to begin the second set before she powered into a 4-0 lead, dropping just one point on serve on her way to leveling up the match.

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 her victory after nearly three hours.

Swiatek will next play 42nd-ranked Czech Marie Bouzkova or Jana Fett, the world No. 135 from Croatia.

Their match was among those to fall foul of the weather as play on all but the main two courts was called off for the day around 1500 GMT, following a five-hour delay.

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, Sinner through

Alcaraz shook off a third-set blip against world No. 176 Jesper de Jong before the Spaniard came through 6-3, 6-4, 2-6, 6-2 under the roof on Court Philippe Chatrier.

Wimbledon champion Alcaraz arrived in Paris with doubts over his fitness after a right forearm injury sidelined him for almost a month.

Third seed Alcaraz looked to be cruising against De Jong, a Dutch qualifier taking part in only his second Grand Slam main draw, but he was ultimately made to work harder than expected.

"Every player can cause you trouble," said Alcaraz.

"You have to be focused in every round, have to play at your best, it doesn't matter what the ranking is."

Second seed Jannik Sinner swept aside home favorite Richard Gasquet 6-4, 6-2, 6-4 in the night session match.

Former French Open finalist Stefanos Tsitsipas reached the last 32 for the sixth straight year with a 6-3, 6-2, 6-7 (2-7), 6-4 win over Germany's Daniel Altmaier.

Sixth seed Andrey Rublev eased aside Pedro Martinez in straight sets, but three-time major champion Stan Wawrinka bowed out to Russia's Pavel Kotov in four sets.