Simona Halep's doping ban has been reduced from four years to nine months by the Court of Arbitration for Sport.
Having already served a provisional suspension since October 2022, she can return to tennis with immediate effect as the nine-month ban expired on July 6, 2023.
The 32-year-old Romanian star was banned by the International Tennis Integrity Agency (ITIA) for "intentional" doping offences.
- How to book Friday's Joshua vs Ngannou fight on Sky Sports Box Office
- NOW Sports Month Membership just £21 a month for 12 months
- Katie Boulter wins San Diego Open title with stunning comeback victory
The CAS Panel determined that "on the balance of probabilities" Halep had not taken the banned substance Roxadustat purposely and while she "did bear some level of fault or negligence for her violations" it was not intentional.
Halep tested positive for Roxadustat after the US Open in August 2022 from a sample taken during the tournament and she was subsequently provisionally suspended in October of last year.
Halep objected to the intentional nature of the charge and argued that the positive test was the result of contamination.
A statement from the CAS panel said: "Having carefully considered all the evidence put before it, the CAS panel determined that Ms Halep had established, on the balance of probabilities, that the Roxadustat entered her body through the consumption of a contaminated supplement which she had used in the days shortly before August 29, 2022 and that the Roxadustat, as detected in her sample, came from that contaminated product.
"As a result, the CAS Panel determined that Ms. Halep had also established, on the balance of probabilities, that her anti-doping rule violations were not intentional.
"Although the CAS Panel found that Ms. Halep did bear some level of fault or negligence for her violations, as she did not exercise sufficient care when using the Keto MCT supplement, it concluded that she bore no significant fault or negligence."
CAS dismissed the biological passport finding, saying: "Contrary to the reasoning of the first instance tribunal, the CAS panel determined that it was appropriate in the circumstances to consider the results of a private blood sample given by Ms Halep on September 9, 2022 in the context of a surgery which occurred shortly thereafter.
"Those results, and Ms Halep's public statements that she did not intend to compete for the remainder of the 2022 calendar year, impacted the plausibility of the doping scenarios relied upon by the International Tennis
Federation independent tribunal.
"Having regard to the evidence as a whole, the CAS panel was not comfortably satisfied that an anti-doping rule violation had occurred. It therefore dismissed that charge."
In a statement, Halep said: "Throughout this long and difficult process, I have maintained my belief that the truth will eventually come out and that a fair decision will be reached because I am and always have been a clean athlete.
"My faith in this process has been tested by the outrageous allegations that have been brought against me and the seemingly unlimited resources that have been aligned against me.
"But in the end, the truth prevailed, even if it took a lot longer than I would have liked.
"I would like to thank my lawyers who stood by me and believed in me from the beginning; and most importantly, I want to thank my sponsors, fans and competitors who have stuck by me through this long and difficult process. I can't wait to get back on the circuit."
The International Tennis Integrity Agency, which oversees tennis' anti-doping programme, has also been ordered to pay Halep around £18,000 as a contribution to her legal fees and expenses.
The ITIA had also appealed seeking an even longer ban, but this is a major victory for Halep, who was staring at the end of her career if the original sanction stood.
The court also ordered that "all results obtained by Halep in competitions taking place between August 29, 2022 - October 7, 2022 are disqualified with all resulting consequences, including forfeiture of any medals, titles, ranking points and prize money."
Halep was the highest-profile tennis player since Maria Sharapova to fail a drugs test, having won the French Open in 2018 and Wimbledon the following year as well as being ranked world number one, and will now look to rebuild her career.
The 2019 Wimbledon winner was later faced with a separate charge with irregularities in her Athlete Biological Passport (ABP) and had not played since October 2022.
Halep won her maiden Grand Slam title at the French Open in 2018 before following it up with more major success at Wimbledon the following year.
Get Sky Sports on WhatsApp!
You can now start receiving messages and alerts for the latest breaking sports news, analysis, in-depth features and videos from our dedicated WhatsApp channel! Find out more here