Petra Kvitova has withdrawn from the French Open after injuring her ankle in a freak fall while performing her post-match media duties on Sunday, the 11th seeded Czech player said in a statement.
Two-times Wimbledon champion Kvitova, who reached the semi-finals at Roland Garros in 2020 and 2012, beat Belgian qualifier Greet Minnen 6-7(3) 7-6(5) 6-1 in her opening match of the tournament and hurt her ankle shortly afterwards.
"It is with great disappointment that I announce my withdrawal from Roland Garros," the 31-year-old Kvitova said on Twitter on Tuesday.
"During my post-match press requirements on Sunday I fell and hurt my ankle.
"Unfortunately after an MRI and much discussion with my team, I have made the tough decision that it would be unwise to play on it. It's incredibly bad luck, but I will stay strong and do my best to recover in time for the grasscourt season."
Kvitova was due to take on unseeded Russian Elena Vesnina in the second round.
Meanwhile, Ashleigh Barty admitted she is struggling with a left hip problem after battling into the second round of the French Open.
The world number one is back at Roland Garros for the first time since winning the title in 2019 and has been in excellent form this season, collecting three titles and cementing her place at the top of the rankings.
She withdrew from her last tournament in Rome because of concerns over an arm problem but took to the court against American Bernarda Pera with strapping at the top of her left thigh.
Barty took a medical time-out to have treatment after Pera won the second set but withstood pressure early on in the deciding set before coming through 6-4 3-6 6-2.
The 25-year-old said: "It's going to be a little bit tough this week. I think over the weekend we had a bit of a flare-up through my left hip, which obviously just needed a bit of help today, needed some assistance to try and release it off as best I could.
"I'm not going to hide behind the fact I’m not quite 100 per cent but I can guarantee that I will go out there with the right attitude every day and be really accepting of that and give it a crack no matter what.
"We’re confident in that we can get my body to a point where I’m able to compete. We’re here, we’re fighting, we’re in with a chance, and that’s all we can do."
Carla Suarez Navarro's inspiring comeback following successful cancer treatment ended with a 3-6 7-6 (4) 6-4 defeat by Sloane Stephens in the opening round.
It was the 32-year-old’s first match since Doha last February, with Suarez Navarro revealing in September that she had been diagnosed with Hodgkin’s lymphoma.
The Spaniard had initially planned to retire at the end of 2020 but, with the coronavirus pandemic halting the tour and then her off-court battle, she decided to continue for another season.
She announced in April she had completed her treatment and been given the all clear, and immediately set about preparing for her return to grand slam action.
For a long time it looked like being a winning return, with Suarez Navarro winning the opening set and serving for the match at 5-4 in the second.
But Stephens, a former finalist at Roland Garros, found her form when she needed to and battled to victory after two hours and 24 minutes.
Suarez Navarro said: "It was a long time, really tough moments. Tough months. But every time I had on my mind that I want to be here, I want to come back. Roland Garros is one of my favourite tournaments, so I had it really clear that my first tournament will be this one.
"Then I tried to prepare myself for my best tennis that I can. Obviously I need more time, but I had a good time this week practising, I had a good level in my match.
"Of course I felt tired at the end. I knew that if I don't close the match in two sets, it will be so difficult for me. But I’m really proud, too, of myself and really happy to have the chance to play here one last time."
Suarez Navarro had not played a tournament since Doha last February, and she said: "Until March 1 of this year, I could not practise full. I started to play with soft balls, I started to play for 20 minutes. Then every day I’m going better. I played a little bit more.
"Of course it was tough. My body felt a lot of change in those months. But I did everything that I could to be here."
The big disappointment was that Paris’ 9pm curfew meant Suarez Navarro bade her farewell to an empty stadium, with Stephens clapping her off court.
Venus Williams, playing in the French Open for a 24th time, suffered a fourth consecutive first-round loss, going down 6-3 6-1 to Ekaterina Alexandrova two weeks shy of her 41st birthday.
Williams' doubles partner Coco Gauff, who has been excellent on the clay this season and is seeded at a slam for the first time, saved multiple set points in an epic first-set tie-break against Aleksandra Krunic on her way to a 7-6 (11) 6-4 victory.
Fifth seed Elina Svitolina had to fight from a break down in the second set against 17-year-old French wild card Oceane Babel before winning 6-2 7-5, while there were also victories for Karolina Pliskova, Jennifer Brady, Maria Sakkari and Ons Jabeur.