The World Anti-Doping Agency (WADA) said it will "present its case robustly again" when the Sun Yang case returns to the Court of Arbitration for Sport.
"The World Anti-Doping Agency (WADA) has been informed of the decision of the Swiss Federal Tribunal to uphold the revision application filed by Chinese swimmer Sun Yang and to set aside the 20 February 2020 award of a Court of Arbitration for Sport (CAS) Panel," said WADA in a statement on Thursday.
"The case is in relation to WADA's successful appeal against the original Federation Internationale de Natation (FINA) disciplinary panel decision following an incident that led to a doping control involving Sun Yang not being completed as planned," it said.
WADA said it had "clearly prevailed on the substance of the case" in the CAS award.
"...it was able to show that there were a number of aspects of the original FINA decision that were incorrect under the World Anti-Doping Code and the related International Standard for Testing and Investigations."
"WADA will take steps to present its case robustly again when the matter returns to the CAS Panel, which will be chaired by a different president," the statement read.
WADA said it had yet to receive the Tribunal's full reasoned decision and therefore cannot comment further.
The CAS found the three-time Olympic champion guilty in February, of refusing to cooperate with sample collectors during a visit to his Hangzhou home in September 2018 and handed him an eight-year ban. Sun then turned to the SFT, his last court of appeal.