The French Open, traditionally held in May-June, was postponed earlier this year due to the COVID-19 pandemic and will now be held at Roland Garros from Sept. 27-Oct. 11.
Serena was scheduled to face Bulgarian Tsvetana Pironkova.
A look at the 10 landmark matches from the 20-times Grand Slam champion's career.
Venus Williams is a two-time mixed doubles winner at Grand Slams, triumphing at the Australian Open and Roland Garros in 1998.
Halep had clinched the French Open in 2018 after defeating American Sloane Stephens in the final.
Simona Halep has been in red-hot form and the absence of top-ranked Australian Ash Barty, who won her maiden Grand Slam in Paris last year, and US Open champion Naomi Osaka, will boost her chances further.
Factbox on Rafael Nadal's French Open final wins
Herbert and Mahut added to their 2018 French Open title after recovering from a shaky start.
Djokovic has won the last three editions of Wimbledon in 2018, 2019 and last year
Rafael Nadal warmed up for the French Open with a battling 7-5, 1-6, 6-3 win over world number one Novak Djokovic as the Spaniard claimed a record-extending 10th Italian Open title in Rome on Sunday in the latest chapter of their rivalry.
Britain's Joe Salisbury and American Desirae Krawczyk capped brilliant Grand Slam campaigns on Saturday, beating Mexico's Giuliana Olmos and El Salvador's Marcelo Arevalo 7-5, 6-2 to lift the US Open mixed doubles title.
Djokovic found a little girl who had held up a sign and ran over to give her a racket, then blew kisses at her.
It was only 13-time champion Rafael Nadal's third defeat here since his debut in 2005 and the first time in 115 best-of-five-set matches on clay that he had lost after taking the opening set.
Most importantly, and most prominently, is the name of Serena's three-year-old daughter Olympia.
Rafael Nadal said on Friday that he intends to compete at Wimbledon later this month
18-year-old Carlos Alcaraz entered the top 10 at the same age, on the same date and after a triumph in the same tournament as compatriot and 21-times major winner Rafael Nadal did in 2005.
Rafael Nadal gets the opportunity to avenge his only defeat in 10 meetings with Diego Schwartzman, which he suffered a little over two weeks ago, when Spain's 12-time French Open winner faces the Argentine in the semi-finals at Roland Garros on Friday.
* Swiatek started playing tennis in an attempt to emulate her older sister, who competed briefly on the junior circuit.
Swiatek made the most of Kasatkina's string of unforced errors, peppering court Philippe Chatrier with winners.
Elena Rybakina's modest celebrations after winning Wimbledon on Saturday was mostly due to her impassive personality but there was possibly also an air of inevitability about her triumph that made her react the way she did.
Organisers in talks with governing bodies amid rescheduling reports.
Romania's Italian Open winner Simona Halep, Spain's Garbine Muguruza and US Open semi-final foe Victoria Azarenka of Belarus present a major challenge for Serena Williams at the upcoming French Open.
The following is a timeline charting her rise to the top of the women's game:
Images from Day 6 of the 2021 French Open at Roland Garros in Paris on Friday.
Like a stern headmaster, a clearly irritated Rafael Nadal beckoned Lorenzo Sonego to the net and gave him an earful about the etiquette of tennis in front of 15,000 wide-eyed fans and a global audience of millions.
French Tennis Federation (FFT) said the start was delayed due to security officials neutralising a vehicle illegally parked outside the stadium.
Serena Williams needs to be creative and add variety to her game if the 39-year-old American wants to tame the current power-hitters on clay, seven-time Grand Slam singles winner Mats Wilander said ahead of this week's French Open.
Those not familiar with seeing Swiatek close up can expect to see her sliding on Wimbledon's grass, as she does on the clay
Swiatek is on a remarkable 34-match winning streak On the other side, Gauff has developed into a solid claycourt player
Surprise package Davidovich Fokina, who knocked out top-ranked Novak Djokovic and Indian Wells champion Taylor Fritz in the earlier rounds at Monaco, drew first blood by breaking Tsitsipas to take a 2-1 lead in the opening set.
Roger Federer will make his only appearance on clay this season at Roland Garros, his agent said. The Swiss skipped the entire claycourt season in 2017 and 2018 and last year played only two tournaments on the surface before arriving in Paris for the French Open.
World champions France moved to four points while Hungary, on one point, kept up their slim hopes alive, in a group where they had been given little chance with heavyweights Germany and Portugal also in the mix.
France's Jo-Wilfried Tsonga is presented with an award after playing his final match before retiring REUTERS/Pascal Rossignol
No Italian man has won a Grand Slam since Adriano Panatta triumphed at Roland Garros in 1976 and if there is any chance that Sinner, Musetti or Berrettini will lift the Musketeers Cup this year, they will face their biggest obstacles in the next round when they take on the might of Nadal, Djokovic and Federer respectively.
Images from Day 8 of the 2021 French Open at Roland Garros in Paris on Sunday
Veteran Indian tennis player Rohan Bopanna and his Croatian partner Franko Skugor advanced to the third round of the French Open with a straight sets win over Americans Frances Tiafo and Nicholas Monroe.
Indian Wells organisers said on Tuesday that world number two Novak Djokovic had been placed in the tournament's draw but it was unclear if the Serbian would be permitted to enter the United States.
Factbox on Rafael Nadal, who beat Novak Djokovic 6-0, 6-2, 7-5 on Sunday to win a record-extending 13th French Open title:
Images from Day 13 of the French Open, at Roland Garros, in Paris.
It was a poor day for former women's Grand Slam champions with Canada's Bianca Andreescu becoming the highest women's seed to fall at the French Open so far, losing a three-hour marathon against Tamara Zidansek.
