Chinese state-run media on Monday blasted Australian swimmer Mack Horton as immoral and his nation as a former "offshore prison", after he referred to homegrown star Sun Yang as a drugs cheat.
Horton dethroned Sun as the 400 metres freestyle Olympic champion at the weekend, prompting the Chinese athlete to break down in tears.
Before the confrontation in the pool, Horton was asked how he felt about doping violators Sun and South Korean Park Tae-Hwan competing at the Games, and responded: "I don't have time or respect for drug cheats."
Sun is a popular hero in China, despite his repeated brushes with controversy -- which include serving a drugs suspension in secret in 2014 -- and the comments lit up nationalistic sentiment online and in print.
The Global Times newspaper, which is close to the ruling Communist party, published an op-ed Monday under a pen name associated with its chief editor blasting Horton's "cynical smugness".
Australia should feel embarrassed by the swimmer's "disgraceful" victory, it said.
"In many serious essays written by Westerners, Australia is mentioned as a country at the fringes of civilisation," it went on, referencing its "early history as Britain's offshore prison".
"This suggests that no one should be surprised at uncivilised acts emanating from the country," it concluded.
Angry Chinese journalists confronted Horton in Rio to ask why he had used such terminology, and the Australian did not mince his words.
"I used the word 'drugs cheat' because he tested positive," replied Horton, setting the tone for an explosive press conference and prompting Chinese officials to demand an apology.
Thousands of social media users also demanded Horton say sorry, posting with the hashtag #SunYangDontCry on China's Twitter-like Weibo service after footage of Sun sobbing uncontrollably in the media zone went viral.
"For the peaceful co-existence of China and Australia, I hereby wish Horton to win swimming titles at the next Paralympics," one user wrote, blasting the Australian as "mentally handicapped".
But Australian media staunchly defended the defiant Horton. The front page of Sydney's Daily Telegraph Monday led with the headline "Clean Machine" over an image of the swimmer and his gold medal, adding that "our superman shows world how to smash drug cheats".
The Australian Olympic Committee also stood by the gold medallist, saying in a statement: "He has spoken out in support of clean athletes. This is something he feels strongly about and good luck to him."
Sun's three-month doping ban in 2014 -- for taking a banned stimulant he said was for a heart complaint -- was only announced after he had completed it.
He returned to the pool Sunday to post the quickest time in the 200m freestyle heats, and refused to take the criticism lying down, growling: "I'm clean. I've proved I'm clean. I don't think we need to concern ourselves with the Australian's mind tricks."