But CAS, sport's highest court, sliced nine months off her ban in what her lawyer John Haggerty described as a "stunning repudiation of the ITF".

In a statement posted on her social media accounts, Sharapova said: "Tennis is my passion and I have missed it. I am counting the days until I can return to the court.

"I have taken responsibility from the very beginning for not knowing that the over-the-counter supplement I had been taking for the last 10 years was no longer allowed.

"But I also learned how much better other federations were at notifying their athletes of the rule change, especially in eastern Europe where Mildronate (its trade name) is commonly taken by millions of people.

"Now that this process is over, I hope the ITF and other relevant tennis anti-doping authorities will study what these other federations did, so that no other tennis player will have to go through what I went through."

The result is undoubtedly a victory for the world's highest-earning female athlete but it is also a defeat for the ITF and the World Anti-Doping Agency.

As both Haggerty and Sharapova pointed out, the three-man panel of CAS experts said it did "not agree with many of the conclusions of the (ITF) tribunal" and the federation has already seen the court reduce recent doping bans for Marin Cilic and Viktor Troicki. The ITF was also chastised by the panel for not properly informing players of changes to WADA's banned list.

Sharapova's lawyers had asked for an immediate reinstatement but deep down they will know the nine-month reduction is the most they could have expected as she did not meet all the criteria for a "no significant fault" reduction of 50 per cent.

CAS said in a statement: "The panel found that Ms Sharapova committed an anti-doping rule violation and that while it was with 'no significant fault', she bore some degree of fault, for which a sanction of 15 months is appropriate."

Sharapova's hopes of complete vindication were holed from the moment her agent Max Eisenbud admitted they failed to check the banned list.

Meldonium was added to the list on January 1, having been on WADA's monitoring list for all of 2015, and athletes and their entourages were warned several times by email that it was about to be prohibited - emails Sharapova did not read.

There was a hint of censure from the panel for Sharapova in that she did not mention her use of meldonium and two other over-the-counter heart treatments on her doping control forms, but her legal team argued she did not do so because she did not take these products every day and did not see the need to list them as they were legal.

Her lawyers also tried to argue that meldonium's very presence on the banned list is a matter of dispute as there is little evidence of its performance-enhancing qualities. CAS did not rule on this but the debate will continue for WADA.

Sharapova, a former world number one, may need to rapidly accumulate ranking points to qualify for the French Open and Wimbledon, unless she is handed wild cards.

Her first event could be the Prague Open, which begins on May 1, the first Monday after her suspension ends, and tournament director Petra Cernoskova told Press Association Sport they would love to have her.

In an email, Cernoskova said: "Great!!!! Yes we are very interested!"

The 2017 French Open is set to run from May 22 until June 11 at Roland Garros, while Wimbledon will take place from July 3 through to July 16.

Press Association Sport contacted officials at both Grand Slam events over whether Sharapova - who won Wimbledon aged just 17 in 2004 and also the French Open in 2012 and 2014 - could potentially be considered for a wildcard next summer.

A spokesman for the All England Lawn Tennis and Croquet Club said: "The decision on wildcards for The Championships 2017 will take place according to the usual protocols and be announced from June 21."