The former world number one was provisionally suspended by the ITF in March after failing the drug test in January.

The five-time grand slam winner said she was not aware that the World Anti-Doping Agency (WADA) had barred athletes from using meldonium, also known as mildronate, as of January 1. She has also previously claimed that she has taken the drug since 2006 for a heart condition.

Her lawyer, John Haggerty, said Sharapova took the substance after that date.

Wednesday's ruling said Sharapova did not intend to cheat, but bore "sole responsibility" and "very significant fault" for the positive test. But the Russian player, who says she will appeal to the Court of Arbitration for Sport, slammed the ITF on her Facebook page:

"While the tribunal concluded correctly that I did not intentionally violate the anti-doping rules, I cannot accept an unfairly harsh two-year suspension," she said.

"The tribunal, whose members were selected by the ITF, agreed that I did not do anything intentionally wrong, yet they seek to keep me from playing tennis for two years. I will immediately appeal the suspension portion of this ruling to CAS, the Court of Arbitration for Sport."

Sharapova criticized the ITF for spending "tremendous amounts of time and resources trying to prove I intentionally violated the anti-doping rules" before adding that "the tribunal concluded I did not".

In addition to testing positive at the Australian Open, she also failed a test for meldonium in an out-of-competition control in Moscow on February 2, the ITF said. Meldonium increases blood flow, which improves exercise capacity by carrying more oxygen to the muscles.

In April, citing a lack of scientific evidence about how long the drug remains in a person's system, WADA said that provisional suspensions may be lifted if it is determined that an athlete took meldonium before it went on the list of banned substances.

About 200 athletes have tested positive for meldonium in 2016 and many, like Sharapova, were Russian. Some said the drug stayed in their systems for months even though they stopped using it in 2015.

But, according to Haggerty, that was not the case for Sharapova.

mp (AP/AFP)