Russian tennis star Maria Sharapova has admitted that she failed a drugs test. The former world number has revealed she tested positive for meldonium at the Australian Open. Speaking at a press conference last night she says it's part of a medicine she's been taking for a decade for health issues, and she didn't realise it was on an updated list of banned substances released at the start of the year. The five-time Grand Slam champion, is provisionally suspended from this weekend pending further action, but says she takes full responsibility, and hopes she'll be able to play again.