Serena Williams has stunned the world of tennis after deciding to withdraw from the French Open a hour before her second-round match.

She was meant to play Tsvetana Pironkova, but pulled out referencing an Achilles injury she suffered at the US Open.

“The Achilles didn't have enough time to heal after the US Open,” said Williams.

“I was struggling to walk and that is a tell-tale sign that I should try to recover.”

The injury means that she will likely miss the rest of 2020 and will play again at the Australian Open in 2021.

“I need four to six weeks of sitting and doing nothing,” said Williams, the Roland Garros champion in 2002, 2013 and 2015. 

“It's more than likely that I won’t play another tournament this year.”

Fans were shocked by the news.

"Feel so bad for Serena, this is really bad news," one fan wrote.

"Sad to hear about Serena Williams' withdrawal from RolandGarros due to an Achilles injury," another wrote. 

Williams thanked them all for their support on Instagram.

"Paris- I love you don’t worry I’ll be back- love you all thanks for the support. Out but not for long," she captioned the snap.