Anderson and Swimming Australia president John Bertrand are both in Horton's corner, as is the Australian Olympic Committee, which has issued a curt reply to China's calls for an apology.

It has been an extraordinary few days in the Rio pool since Fairfax Media first revealed a rift between Horton and Yang, a double Olympic gold medallist from London.

Horton labelled Sun a drug cheat after his heats and boldly stood by the call after winning a nail-biting final.

It has outraged Sun, the Chinese swimming team and it seems the nation as a whole. Sun is a mega-star in his homeland and Horton (and indeed any western journalist writing about Horton) has been subjected to online abuse and endless trolling.

But it has also galvanised widespread support for Horton from current and past athletes who applauded his outspoken stance on doping at a Games where it has taken centre stage.

Sun was given a secret three-month ban in 2014 and many rivals resent his presence in the sport.

Anderson has been at the forefront of the dramatic turnaround within Swimming Australia and was not going to leave Horton hanging.

He said that while there was no over-arching narrative from Swimming Australia on the doping issue at the Games, swimmers were encouraged to follow their own leads.

"We do support our athletes and trust them that when they say things, they say them with respect and openness and transparency.

“Mack made that statement and we absolutely back it. He then needed to come out and deliver and he did," Anderson told Fairfax Media.

"Before we started, we said we weren't going to have a position that we are overt about it, and it's up to the athletes.

“Every athlete is going to be different. What we didn't want is it to be a distraction for the team.

"We're not focusing on that as a topic but clearly it is something that meant a lot to Mack. He came out, made a strong statement and we support that.

"You saw that all unfold over a few days and he's (Horton) grown as an athlete and a person. It sets it up well for a great race (1500m) at the end of the week. Mack will now focus on preparing for that race."

And from the AOC: "Mack is entitled to express a point of view. Under the Team Values ASPIRE the E stands for express yourself, that is his right. He has spoken out in support of clean athletes. This is something he feels strongly about and good luck to him."

That response was to Chinese swimming team manager Xu Qi, who demanded an apology from Horton. That won't be forthcoming.

"We have been noticing what has been said in the past two days by Horton, who launched a malicious personal attack (on Chinese swimmers)," Xu Qi said on Sunday.

"We think his inappropriate words greatly hurt the feelings between Chinese and Australian swimmers. It is proof of a lack of good manners and upbringing. We strongly demand an apology from this swimmer."

This is the same Xu Qi that initially derided Fairfax Media's coverage of the training incident as 'fake news', while other Chinese state-run media have gone as far as suggesting Horton refused to shake Sun's hand after the race, despite the pair shaking and embracing for photos on numerous occasions.

"Horton's low slander of Sun Yang" was a top-trending hashtag topic on China's Twitter-like Weibo on Monday morning, amassing more than six million views.

Footage of a devastated Sun bursting into tears in the media mixed zone immediately after the race also went swiftly viral on Chinese social media, with the hashtag "Sun Yang Don't Cry" now having reached more than 190 million Weibo users.

If nations are going to start making complaints about clean athletes taking aim at dopers, it could be a long Olympics. After missing the semi-final by one place to Russia's Yulia Efimova, Ireland's breaststroker Fiona Doyle held little back.

"Cheaters are cheaters. She [Efimova] has tested positive five times and she's gotten away with it again. It's like FINA keep going back on their word and the IOC keep going back on their word.

"And FINA caved in to [Vladimir] Putin, and that's just not fair on the rest of the athletes who are clean. Who are you supposed to trust now?"

Doyle had dreamed of her Olympic moment since she was 12. Instead, her place was filled by Efimova, who was banned for an anabolic steroid for 16 months in 2013 and again this year for meldonium.

This issue barely simmered before igniting in Rio. It makes the Sun-Horton reunion in the 1500m on the final night at the pool all the more mouth-watering. 

- with Philip Wen