Wimbledon 2021: Serena Williams retires injured against Aliaksandra Sasnovich

American great Serena Williams says she is "heartbroken" after her latest attempt for a record-equalling 24th Grand Slam was cruelly ended by injury.

Williams started against Aliaksandra Sasnovich with heavy strapping on her thigh and slipped in the fifth game.

The 39-year-old went down again in the seventh game and was overcome by emotion before having to retire.

Centre Court gave a standing ovation as she left, with Williams later saying: "The court meant the world to me."

Williams, seeded sixth, seemed to do the damage when she rocked backwards on the baseline before unleashing a forehand back to her opponent.

After going off court for treatment, the seven-time SW19 champion returned with a heavy limp and tried to continue before it soon became apparent she would be unable to.

Tears filled her eyes as Williams thanked the crowd, who had been trying to encourage her, for their support.

At 15-15 on her service game at 3-3, Williams buckled as she prepared to receive a return and spent a few moments kneeled on the court.

The umpire came down off her chair as Williams slowly managed to climb to her feet.

Fans on Centre Court rose in unison to give a heartfelt standing ovation as Williams waved goodbye - with the crowd no doubt wondering if this will be the final time at SW19 for a player who turns 40 in September.

"I was heartbroken to have to withdraw today after injuring my right leg," Williams said in an Instagram post later on Tuesday.

"My love and gratitude are with the fans and the team who make being on Centre Court so meaningful.

"Feeling the extraordinary warmth and support of the crowd when I walked on - and off - the court meant the world to me."

The retirement came within an hour of Centre Court watching France's Adrian Mannarino also have to retire from his match against Roger Federer.

The 33-year-old slipped on the same baseline, leading to Britain's Andy Murray - who had played there on Monday - tweeting about the surface.

It was a cruel blow for Williams, who had broken for a 3-1 lead.

"I'm so sad for Serena. She is a great champion," said Belarusian world number 100 Sasnovich.

"It happens sometimes in tennis, but all the best to her."

After losing to Simona Halep in the 2019 final - and finishing runner-up to Germany's Angelique Kerber the year before - Williams was hoping this would finally be the time that she won her 24th Grand Slam.

Matching the number won by Australian Margaret Court has so far proved beyond her, having lost four major finals since returning from maternity leave three years ago.

The Wimbledon grass seemed the place most likely to yield another major but it will not be this year, at least.

"I feel sad for Serena. I sincerely hope it is not the last time we see her at Wimbledon," said 2013 champion Marion Bartoli on the BBC's 'Today at Wimbledon' programme.

"The way she waved at the crowd, and put her hand on the heart to show her appreciation, I hope it is not a farewell.

"I still feel she can win that 24th major, she has it inside her. The amount of injury and bad luck of sliding is such a shame."