The administrator of the Tennis Anti-Doping Programme denied it had sought a four-year ban for the former world number one and, in a statement, rejected suggestions by the Russian that its independent tribunal was "not neutral"
The International Tennis Federation (ITF) hit back on Thursday at criticism over its handling of Maria Sharapova's drugs ban for meldonium.
The administrator of the Tennis Anti-Doping Programme denied it had sought a four-year ban for the former world number one and, in a statement, rejected suggestions by the Russian that its independent tribunal was "not neutral".
The ITF also emphasised it had not known, prior to this year when the drug was put on the banned list, that meldonium was in common use by eastern European athletes.
Five-time grand slam winner Sharapova was cleared by the Court of Arbitration for Sport to return to action in April after her two-year suspension was reduced to 15 months on Tuesday.
The 29-year-old said then that other sports federations had been more effective at communicating with athletes and hoped the ITF would take note.
Her lawyer John Haggerty described the ITF's procedure for relaying rule changes as a "night and day difference" to the "vivid and direct warnings" from others.
"The ITF did not try to ban Ms. Sharapova for four years, as has been suggested," the tennis governing body said.
"The ITF stated clearly that it was the responsibility of the Independent Tribunal -- and subsequently the CAS Panel -- to determine what the appropriate sanction should be.
"Ms. Sharapova has stated that the Independent Tribunal was ‘not neutral’," it added.
"Ms. Sharapova’s legal team was given the opportunity to object to the appointment of any member of that Tribunal in advance of the hearing, and they agreed in writing that they had no such objection."
The ITF believed it had taken appropriate steps to publicise changes to the prohibited list and it was "not true" to say that it was aware of widespread use of meldonium in Eastern Europe and should have given specific notice.
"In fact, it was accepted by Ms. Sharapova in the hearing before CAS that the ITF did not know before 2016 about the extent to which meldonium was used by athletes from any region, or that Ms. Sharapova herself was using meldonium," it said.
The ITF pointed out that the WADA monitoring programme is conducted anonymously and WADA "does not inform any anti-doping organisation about the prevalence of such use until it publishes the results of the monitoring programme."
It said that was May 2016 for the 2015 monitoring programme.
IMAGE: Russia's Maria Sharapova reacts during a news conference
Photograph: John French/File Photo/Reuters.