Australian Mack Horton ripped into Chinese giant Sun Yang for his doping record Saturday after robbing him of his Olympic men's 400 metres freestyle title.

Blinking shyly behind his spectacles, Horton added insult to injury as he backed up remarks he made earlier in the day with a pulsating victory in Rio.

Asked for his thoughts on doping violators Sun and South Korean Park Tae-Hwan competing at the Games, Horton sniffed: "I don't have time or respect for drug cheats."

That prompted an outcry from Chinese journalists who sabotaged Horton's victory press conference demanding to know why he had used such frank language.

"I used the word 'drugs cheat' because he tested positive," replied Horton. "It's not a question about me and Sun. I just have a problem with athletes who've tested positive and are still competing."

The row overshadowed a race that had everything -- lead changes galore and a thunderous finish, Horton refusing to flinch as he won by a fingertip, edging Sun to win by just 0.13 seconds in a time of 3:41.55.

Italy's Gabriele Detti roared home in the final 50 meters to capture bronze in 3:43.49 but the race merely proved to be the 'amuse bouche' to the verbal skirmishes that followed.

"That last 50 I was kinda thinking about what I said and was like 'if he gets me here it's not going to look great' so I really didn't have a choice but to beat him," grinned Horton.

Typically, swimming's 'enfant terrible' did not take Horton's criticism lying down, snapping back: "I don't care too much what the Australian athlete says. I don't have to prove myself to anyone."

However, Sun did offer an apology for his behaviour over the past few years. "It's been tough and I know I've made mistakes, but I know how to face up to failure and have a broader perspective."