Maria Sharapova has had her doping ban cut from two years to 15 months by the Court of Arbitration for Sport (CAS).
Sharapova was the subject of a suspension that was due to run until January 2018, after testing positive for banned substance meldonium at this year's Australian Open.
The former world number one claimed to be unaware that meldonium had been added to WADA's prohibited list at the start of 2016 and duly appealed to CAS.
A statement from the International Tennis Federation (ITF) on Tuesday confirmed Sharapova's ban would now run until April 2017.
Explaining the decision, the statement read: "Following a hearing on 7 and 8 September 2016, the CAS panel found that Ms Sharapova had a reduced perception of the risk that she took while using Mildronate, because (a) she had used Mildronate for around 10 years without any anti-doping issue, (b) she had consulted the Russian doctor who prescribed the Mildronate for medical reasons, not to enhance her performance, and (c) she had received no specific warning about the change in status of meldonium from WADA, the ITF, or the WTA.
"In addition, the CAS panel considered that it was reasonable for Ms Sharapova to entrust the checking of the Prohibited List each year to her agent.
"However, the CAS panel found that Ms Sharapova was at fault for (a) failing to give her agent adequate instructions as to how to carry out the important task of checking the Prohibited List, and (b) failing to supervise and control the actions of her agent in carrying out that task (specifically the lack of any procedure for reporting or follow-up verification to make sure that her agent had actually discharged his duty).
"The CAS panel also noted Ms Sharapova's failure to disclose her use of meldonium on her doping control forms.
"Taking all of these circumstances into account, the CAS panel determined that, although Ms Sharapova was at fault, her plea of No Significant Fault or Negligence should be upheld, triggering a discretion to reduce the otherwise applicable two-year sanction by up to 50 per cent.
"Based on its analysis of Ms Sharapova's degree of fault, the CAS panel decided that the sanction should be reduced in this case to 15 months."