A long-anticipated hearing of doping charges against China's Olympic hero Sun Yang was on Friday night at risk of being lost in translation, with much of the swimmer’s testimony to the Court of Arbitration for Sport rendered incomprehensible.

Sun Yang, the bitter rival of Australia’s Mack Horton whose career has been dogged by doping allegations, is facing a career-ending ban for refusing to submit a urine sample and tampering with a blood sample during a late night drug test last year at his Hangzhou home.

Australia's Mack Horton refuses to share the podium with Yang Sun at this year’s swimming world championships in South Korea. Credit:AP

Despite the significance of the hearing which, in a break from convention, is open to the public, Sun Yang’s explanation of the bizarre chain of events that took place during the aborted drug testing mission was garbled by a poor translation service.

Sun Yang’s case is that he refused to provide a urine sample and later, broke into a secure box to retrieve a blood sample he had already given, because members of the drug testing team were acting suspiciously and lacked proper accreditation.