Sun won two gold medals at the 2012 London Olympic games and another in Rio de Janeiro in 2016.
CNN  — 

China’s triple Olympic swimming champion Sun Yang has had an eight-year doping ban “set aside” by the Swiss Federal Supreme Court in a ruling that could prove highly embarrassing for the Court of Arbitration for Sport (CAS) and a former Italian Foreign Minister.

Switzerland’s CAS is seen as sport’s final court of judgment and it’s rare for its decisions to be challenged by the Swiss legal system.

In a statement the World Anti-Doping Agency (WADA) said it noted that the Swiss Federal Tribunal had upheld “a challenge against the Chair of the CAS Panel and makes no comment on the substance of this case.”

The original CAS panel comprised former Italian Foreign Minister Franco Frattini – who is also an Italian magistrate – as well as Belgian lawyer Romano Subiotto and British lawyer Philippe Sands. CAS listed Frattini as the panel’s President

The Swiss Federal Supreme Court overturned Sun’s CAS ban “on the grounds of bias” on Tuesday.

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Sun had been given the ban for refusing to complete an out-of-competition doping test. In February, CAS accepted an appeal from WADA against a decision by the world swimming body FINA to clear the Chinese swimmer of wrongdoing for his conduct during the test in September 2018.

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‘Different composition of the panel’

But in the latest legal twist, Sun’s legal team successfully challenged the CAS ruling.

“The Swiss Federal Supreme Court approved the request by the Chinese swimmer Sun Yang for revision of the arbitral award of the Court of Arbitration for Sport (CAS) in Lausanne dated 28 February 2020 on the grounds of bias of one of the arbitrators of the CAS,” said a statement from the Swiss Federal Supreme Court sent to CNN on Thursday. ​

“The award of the CAS is set aside,” added the statement. “The CAS will have to render a new award in the case of Sun Yang in a different composition of the panel. The reasoning of the judgment of the Federal Supreme Court is not yet available.”

WADA said on Wednesday it plans to “present its case robustly again when the matter returns to the CAS Panel, which will be chaired by a different president.”

Sun Yang competes in the men's 1500m Freestyle final on Day 8 of the London 2012 Olympic Games at the Aquatics Centre on August 4, 2012 in London, England.

Frattini has posted on Twitter about the treatment of animals in China, ​including using an anti-Chinese slur.

The former Italian Foreign Minister declined to comment when contacted by CNN, saying he wanted to be able to read the court’s full reasoning first.

Sands did not immediately respond to CNN’s request for comment. Subiotto referred CNN to CAS Secretary General Matthieu Reeb. The CAS did not immediately respond to CNN’s request for comment.

Sun, 29, is one of China’s top athletes, having won two gold medals at the 2012 London Olympic games and another in Rio de Janeiro in 2016.

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Eight years is the maximum ban that CAS can hand out. Sun previously served a ​three-month doping ban in 2014.

It’s unclear when a new CAS panel will sit to adjudicate on the Sun case. The Chinese swimmer won’t be banned from competing, pending the outcome of the CAS hearing.

The Chinese Olympic Committee and FINA – swimming’s world governing body – did not immediately respond to CNN’s request for comment. Neither did members of Sun’s legal team.

Additional reporting Jill Martin, Zayn Nabbi and Sharon Braithwaite