Disgraced Chinese swimmer Sun Yang has made a last-ditch attempt for eligibility at the Tokyo Olympics by lodging an appeal against his eight-year ban.

The controversial 28-year-old has was hit with the suspension in February following a drug test in September 2018 when a vial of his blood was destroyed by his mother.

The Australian reports that Yang’s appeal was lodged to the Swiss federal court on April 29 in response to the long punishment handed to him by the Court of Arbitration for Sport.

Yang has claimed the correct testing procedures were not followed and believed the drug tester was not fully accredited to take the blood.

The world swimming body FINA had originally cleared Yang to compete after an internal investigation of the blood testing furore, but the World Anti-Doping Agency successfully appealed the decision at the Court of Arbitration for Sport.