Paris: Serena Williams announced her shock withdrawal from the French Open on Monday with injury just minutes before her scheduled fourth-round clash against long-time bitter rival and fellow Grand Slam icon Maria Sharapova.

The 36-year-old said she had suffered a pectoral muscle injury in her third-round win over Julia Goerges and “can’t serve at all”.

The 23-time Grand Slam champion added that she would stay in Paris for scans on the injury to find out how long she will be out of action.

“I unfortunately have been having some issues with my pec, my pec muscle, and (it) has unfortunately been getting worse to the point where right now I can’t actually serve. It’s kind of hard to play when I can’t physically serve,” she explained.

She was unable to say whether or not she would be fit for Wimbledon which gets under way in four weeks’ time.

“I’m beyond disappointed,” added three-time Roland Garros champion Williams who was playing in her first Grand Slam since winning the 2017 Australian Open.

She was also playing just her third tournament of the year after giving birth to daughter Olympia in September.

“I gave up so much time with my daughter and time with my family all for this moment. So it’s really difficult to be in this situation.”

The shock withdrawal came just minutes before she was due on Court Philippe Chatrier to face fierce rival Sharapova.

Williams has not lost to the Russian since 2004, winning the last 18 matches.

Earlier, current world No. 1 and top seed Simona Halep blazed into the quarter-finals by crushing Belgian Elise Mertens 6-2 6-1 as she showed her full range of weapons.

The 26-year-old Romanian started slowly but once she found her groove, there was nothing the 16th seed could do to avoid a one-sided defeat.

“I don’t know how the other players are before the matches, but I think I am very nervous before every match, and this is because I am like this,” said Halep, who will next meet either German Angelique Kerber or local favourite Caroline Garcia.

“So I’m not going to fight with myself about that. But I try to improve this thing, and I try to enjoy my nerves, because they are special when you play in a Grand Slam.”

Despite the nerves, Halep was way too good for her 22-year-old opponent on Court Philippe Chatrier.

Mertens entered the tournament having won two second-tier events on clay including 16 wins and one defeat, albeit against Halep last month in Madrid when she was comprehensively beaten.

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.

Saved by fading light the night before, there was no escape for world number two Caroline Wozniacki on Monday as Russian Daria Kasatkina completed a 7-6(5) 6-3 victory to reach the fourth round of the French Open.

Kasatkina, the 14th seed, had played beautifully to lead 7-6 3-3 on Sunday when play was called off but any hopes Australian Open champion Wozniacki harboured that her 21-year-old opponent’s level would dip on the resumption proved fanciful.

It was all over in a matter of minutes on Court Philippe Chatrier as Kasatkina rattled off the three games she needed to reach her first Grand Slam quarter-final.

Having disposed of one reigning Grand Slam champion, Kasatkina, who has dropped just one set so far, will next face another in US Open winner Sloane Stephens.