BEIJING - The World Anti-Doping Agency (WADA) said it would "present its case robustly again" after the Swiss Federal Tribunal (SFT) upheld Sun Yang's appeal and set aside the previous ruling by the Court of Arbitration for Sport (CAS) to ban the Chinese swimmer for eight years.

According to the WADA's statement, when the case returns to the CAS panel, it will be chaired by a different chairperson.

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. Sources told Xinhua early Thursday Beijing time that the SFT has overturned the CAS ruling, which could give Sun a chance to compete at the postponed Tokyo Olympic Games next year.

"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.

"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.

Sun's case was first heard by swimming's world governing body FINA, who decided on January 3, 2019, that the swimmer was not guilty of anti-doping rule violations. WADA disagreed and appealed the decision to the CAS.

As requested by Sun, the CAS held only its second public hearing in November 2019, which was marred by poor translation. The CAS later was forced to ask all parties to submit a written transcript of proceedings, including a full translation of Sun's testimony.

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.

In WADA's statement, it mentioned the Swiss Federal Tribunal decided to uphold "a challenge against the Chair of the CAS Panel," which seems to reveal at least part of the reasons for the SFT to set aside the CAS ruling.

Then CAS panel chair Franco Frattini informed Sun after the 11-hour hearing in February to be "sure of two things that he has the full right to be heard and is completely respected."

In addition, Frattini had been revealed making racist comments about China on social media. "This yellow face chinese monster smiling while torturing a small dog, deserves the worst of the hell!!!" the CAS Chair tweeted in 2019 in response to an unverified video of an unknown market seller.

The year before the Italian tweeted, "Hell forever for those b*****d sadic (sic) chinese." Observers have maintained whether Frattini was the right person to chair the Sun Yang case after a string of abusive tweets over a number of years aimed at China.