Her total of 23 Grand Slam singles titles marks the record for the most Grand Slam wins by a tennis player in the Open Era.
The scene had been set for Williams in her "superhero" catsuit to take on Russian ice queen Maria Sharapova in a fourth-round clash that had assumed top billing.
"I'm beyond disappointed. I gave up so much and gave everything on the court, all for this moment", Williams told a hastily-arranged news conference.
The story was the same on Monday as Halep, a French Open finalist in 2014 and 2017, broke for 2-1 in the opening set and never looked back as she outmanoeuvred Mertens, who was sent chasing the ball all over the court.
Despite playing just four matches in 2018 before Roland Garros, Williams played doubles in Paris with sister Venus.
Williams' voice quivered as she said she can't serve because of a problem with her tight pectoral muscle.
Mouratoglou said they held a practice session Monday morning, holding out hope that maybe rain in the forecast would postpone the match against Sharapova. "So it's just, like, I think it would be more shocking if I wasn't in tears".
The 26-year-old made the French Open final last year but was beaten by Jelena Ostapenko in one of her previous three failed attempts at the last hurdle of a major.More news: Rafael Nadal loses shock first set against fired up Diego Schwartzman
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"She's a tough opponent", said Wozniacki.
"I tried a lot of different tapings and support and it didn't really get a lot better", the American added. It's just her game matches so well against mine.
In her last 18 straight losses to Serena, Sharapova has been able to take only three sets off her. "At least all the stuff I read and the quotes that I read, which was a little bit disappointing".
Kasatkina, the 14th seed, will meet another Grand Slam victor, US Open champion Sloane Stephens, in the final eight.
"I have made every sacrifice that I could".
At the heart of this claim lies the absolute annihilation of some of the best to play with her, repeatedly. And while she's "pretty much had every injury in the book", this was the first time dealing with this particular malady.
"She was keen on playing Serena". I think it's normal. "Everybody looked forward to this match", Hogstedt said. The first time I felt it was against Goerges in my last match. "This match has had so much build-up".