Navratilova backs Maria Sharapova over failed drugs test - reaction from the world of sport

The nine-times Wimbledon champion wrote on Twitter that she hopes the matter gets cleared up after the Russian told a press conference in America that she had taken the banned substance meldonium.

Jennifer Capriati was less sympathetic, however, in a series of posts on Twitter.

"I'm extremely angry and disappointed. I had to lose my career and never opted to cheat no matter what. I had to throw in the towel and suffer," she wrote.

Capriati was attacked on her Twitter page by Sharapova fans, and went back onto the social media site to defend herself.

Sharapova said she has been taking the substance since 2006 to combat a family history of diabetes and irregular EKGs (electrocardiograms that monitor the activity of the heart) but failed to pick up on an email from WADA with the updated list of banned drugs sent out late last year.

"I made a huge mistake," said Sharapova. "I let my fans down. I let my sport down that I've been playing since the age of four that I love so deeply."

Andy Murray's former coach Brad Gilbert blamed the Russian star's team for the oversight, saying that he was, "still stunned that nobody on Shazza team checked new list from WADA, players are responsible but this is big time oversight on team as well."

But there was plenty of support for the Russian. Former player James Blake insisted it was the right decision for Sharapova to take responsibility for her actions and announce it publicly.

Another American player, Ryan Harrison, praised Sharapova's handling of the situation in glowing terms: "Maria handled that so well. In my opinion, honest mistake from a great champion."

Former heptathlete Kelly Sotherton was less sympathetic. Like Capriati, she alluded to the fact that Sharapova appears to be receiving special treatment thanks to her status and image, and the fact that she is a tennis player rather than an athlete or cyclist.

She did also say it was refreshing to hear Sharapova take responsibility for it herself.

Much of the reaction and debate focused on the reasons Sharapova had for taking the medicine - and asking whether or not it was justified.

British 400m runner - and Olympic bronze medallist - Katharine Merry made it clear which side of the debate she was on, saying, "I am sick of hearing about athletes taking medicines for conditions they don't have."

Steve Simon, the head of the WTA insisted Sharapova is a "leader" who has shown great "integrity" and he was saddened to hear the news.