Chinese superstar swimmer Sun Yang declared war on Australian rival Mack Horton, telling him before a showdown in the 1,500 metres freestyle that he is the “king”. The day after Sun failed to defend his title in the 400 metres freestyle against Horton, he said he was “no friend” of Horton. “1,500 metres, I am the king,” Sun, 24, told Australia’s Channel Seven network outside the Rio Olympics aquatic centre. Tensions between the two flared when Horton, 20, described Sun as a “drug cheat”. And China and Australia also became embroiled in a spat, with mainland state-run media blasting Horton’s homeland as a former “offshore prison”. WATCH: Golden moments on Day 2 The Australian swimmer beat Sun in the 400 metres freestyle by a split second. He clocked three minutes, 41.55 seconds, while Sun finished in 3:41.68. Horton defended his decision to describe his opponent as a drug cheat, saying he used the words because “I have a problem with him testing positive and still competing”. The Chinese Swimming Association wrote to its Australian counterpart to demand an apology from Horton. Sun shower: tearful Sun Yang accuses conqueror Mack Horton of dirty tricks after Rio loss “We are concerned that Australian athlete Mack Horton has made malicious attacks [on Sun],” the letter reads. “We think that his inappropriate comments have greatly harmed the relations of China and Australia, as well as the image of Australian athletes. He has shown a lack of personal quality and manner. We strongly demand the athlete apologise”. Social media was flooded with comments criticising Horton’s accusations. 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. Sun Yang outshone by Australian rival Mack Horton in men’s 400m freestyle Olympic final “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”. A post on Horton’s Facebook page of him with the gold medal has drawn more than 42,000 comments just a day after his victory. Most of the comments were from angry Chinese fans, who described the Australian swimmer as “rubbish” and “a dog”. Sun’s mother, Yang Ming, wrote on her Wechat account that she and Sun’s father had both shed tears after seeing their son break down after losing to Horton. Yang said her son had sustained bone fractures while he was training in Australia in January, but knew that Sun had been determined to swim. “Sun Yang, you really don’t have to blame yourself. You have tried your best. You still have competitions to come, so wipe off your tears and embrace the races. Dad and mum are proud of you and will be rooting for you,” Yang said. WATCH: Relive the action involving Hong Kong athletes on Day 2 Sun will face off against Horton in the same 1,500m qualifying heat on Friday. The finals will take place the next day. Meanwhile, in China the state-run Global Times blasted Horton for his “disgraceful” victory and his “cynical smugness”. It went on to say that in many serious essays written by Westerners, Australia is mentioned as a country at the “fringes of civilisation”, and mentioned the country’s “early history as Britain’s offshore prison”. “This suggests that no one should be surprised at uncivilised acts emanating from the country,” it concluded. The Australian Olympic Committee has thrown its support behind Horton, saying he has spoken out in support of clean athletes. Australian media staunchly defended the defiant Horton. The front page of Sydney’s Daily Telegraph on 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”.