Russian superstar Maria Sharapova has appealed to the Court of Arbitration for Sport against her two-year doping ban, CAS confirmed on Tuesday.
The 29-year-old tested positive for the controversial banned medication meldonium during January's Australian Open.
The ban, announced by the International Tennis Federation last week, is backdated to January 26 this year, when she tested positive for the prohibited substance.
"In her appeal to the CAS, Ms Sharapova seeks the annulment of the Tribunal's decision to sanction her with a two-year period of ineligibility further to an anti-doping rule violation," CAS said in a statement, adding that a decision would be made by July 18 at the latest.
"Ms Sharapova submits that the period of ineligibility should be eliminated, or in the alternative, reduced."
If her appeal is unsuccessful the five-time Grand Slam champion will miss the Olympic Games in Rio in August while the earliest Grand Slam she could next enter is the French Open in 2018.
Sharapova blasted the ban as "unfairly harsh" in a statement 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," fumed Sharapova.
"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."
Meldonium was added to the world anti-doping WADA list on January 1. Sharapova said she'd been taking it for 10 years to help treat illnesses, a heart issue and a magnesium deficiency.