Olympic swimming champion Sun Yang will miss the 2020 Games in Tokyo after being banned for eight years for breaching anti-doping rules.
The Court of Arbitration for Sport (CAS) has upheld the World Anti-Doping Agency's (WADA) appeal against a decision by swimming's governing body FINA to clear him of a doping offence in 2018.
The decision means Sun will not be allowed to defend his 200m freestyle title at the Olympic Games in Tokyo and effectively ends his career.
He said he will "definitely" appeal the decision to the Swiss Federal Tribunal.
Sun was accused of smashing the vials containing his blood after a row with a team of FINA drug-testers at his home in September 2018.
The 28-year-old, his mother and entourage allegedly interfered with the FINA team's efforts to get samples because they did not believe the testers were properly accredited or qualified.
The ruling from CAS read: "The CAS Panel unanimously determined, to its comfortable satisfaction, that the Athlete violated Article 2.5 FINA DC (Tampering with any part of Doping Control).
"It is one thing, having provided a blood sample, to question the accreditation of the testing personnel while keeping the intact samples in the possession of the testing authorities; it is quite another thing, after lengthy exchanges and warnings as to the consequences, to act in such a way that results in destroying the sample containers, thereby eliminating any chance of testing the sample at a later stage."
Sun's clash with Duncan Scott at World Aquatics Championships
Sky Sports News reporter Jamie Weir
Sun had already served a three-month ban for an earlier offence, but was cleared by a subsequent FINA investigation, a decision which prompted a mixture of fury and incredulity around the swimming world.
That was evident at the World Aquatics Championships in South Korea last July, when Sun claimed his 10th and 11th world titles but also clashed with Australia's Mack Horton and Britain's Duncan Scott during medal ceremonies.
On stepping onto the podium to collect his gold medal, Sun turned and aggressively screamed in the face of Scott, who won bronze for finishing joint third.
He then shook hands with the other two medallists but refused to shake hands with Scott.
As all four swimmers were leaving the podium, Sun turned back and, inches from Scott's face, said "You are a loser, I am a winner". The British swimmer refused to react.
Scott has reacted to Sun's ban with the following statement.
"I fully respect and support the decision that has been made by CAS this morning. I believe in clean sport and a level playing field for all athletes and I trust in CAS and WADA to uphold these values."