Tennis star Maria Sharapova lashes out at critics

California: Maria Sharapova hit back Friday at suggestions she received five separate warnings about changes to tennis anti-doping rules which ultimately led to her testing positive for a banned drug.

A defiant Sharapova defended herself in a post on her Facebook page, saying that she received one clear notice in December titled "Main Changes to the Tennis Anti-Doping Programme for 2016."

"I should have paid more attention to it. But the other "communications"? They were buried in newsletters, websites, or handouts," the Russian star said.

Former world number one Sharapova announced Monday that she failed a drug test at the Australian Open in January.

Sharapova tested positive for meldonium, which was added to the World Anti-Doping Agency`s banned list on January 1.

Sharapova also said she wants to set the record straight because there is a lot of misinformation going around about her situation.

"I am determined to fight back," she said. "No excuses, but it`s wrong to say I was warned five times."