"I received a letter from the ITF that I failed a drugs test at the Australian Open," said Sharapova. "I take full responsibility for it.

"For the past 10 years I have been given a medicine called mildronate by my family doctor and a few days ago after I received the ITF letter I found out that it also has another name of meldonium which I did not know.

"It is very important for you to understand that for 10 years this medicine was not on Wada's banned list and I had legally been taking the medicine for the past 10 years.

"But on January 1st the rules had changed and meldonium became a prohibited substance which I had not known."