Former world number one Maria Sharapova has revealed she failed a drugs test at the Australian Open. The 28 year old Russian star tested positive for meldonium, a substance, she has been taking since 2006 for health issues. The International Tennis Federation said, Sharapova, a five time Grand Slam champion, is provisionally suspended from March 12th pending further action. Meanwhile, sportswear maker Nike has suspended their relationship with Sharapova till the investigation continues. Sharapova, who lives in Florida, provided the anti-doping sample in question on January 26th, the day she lost to Serena Williams in the Australian Open quarter finals.