Sun Yang launched a furious tirade at bronze medal winner Duncan Scott after the controversial Chinese swimmer took gold with the help of a disqualification in the 200 metres freestyle at the World Championships.
Lithuania's Danas Rapsys was denied a first world title as he was disqualified for movement on the blocks, handing victory to China's Sun, who served a three-month ban for testing positive for a banned stimulant in 2014.
There had been controversy after Sun won the 400m freestyle on Sunday when Australia's Mack Horton refused to stand on the podium with him.
Scott followed suit on Wednesday after he finished in a dead heat for the bronze.
Sun was left furious after Scott shunned a handshake. Sun berated the Briton from the top step of the podium before the Chinese anthem was played, continuing to point the finger at Scott after the medal ceremony.
It appeared as if Sun told Scott, "You're a loser, I'm a winner", but those words seemed to have little affect on the bronze medallist, as Scott said: "I'm team Mack.
"If [Sun] can't respect our sport then why should I respect him? I think a lot of people, everyone in swimming, got behind what Mack did."
Sun is currently the subject of an appeal by the World Anti-Doping Agency [WADA] to the Court of Arbitration for Sport, with WADA challenging a decision by swimming's global governing body FINA not to punish Sun over allegations stemming from a visit by out-of-competition testers in September 2018. Sun denies all wrongdoing and has requested a public hearing.
There was more Chinese success in Gwangju as Xu Jiayu impressively defended his 100m backstroke title, with Canada's Kylie Masse doing the same in the women's edition of that race.
Illness kept US star Katie Ledecky out of the final of the 1,500m freestyle and Simona Quadarella profited in her absence, the Italian adding to the European title she won in that event last year.
Olympic and world champion Lilly King led from start to finish in the 100m breaststroke as the American successfully defended the title, while Great Britain's Adam Peaty was just 0.16 seconds shy of his own world record in the semi-finals of the 50m breaststroke.