Hungarian teenager Kristof Milak smashed Michael Phelps's 200m butterfly world record. — AFP Photo

GWANGJU, South Korea — Chinese giant Sun Yang suffered defeat on Wednesday after an emotional week in which he has clashed with rival swimmers over doping allegations, while Hungarian teenager Kristof Milak shattered Michael Phelps's 200m butterfly world record.

Triple Olympic champion Sun had already retained his 200 and 400m crown in Gwangju but he finished a distant sixth in the 800m final behind Italian Gregorio Paltrinieri, who claimed gold in seven minutes, 39.27 seconds from Norway's Henrik Christiansen.

A brutal schedule looked to have taken its toll on Sun, who has been involved in angry confrontations with Australian Mack Horton and Britain's Duncan Scott after they snubbed him at two different medal ceremonies in response to bombshell claims made in a FINA doping panel report.

The leaked document alleged that Sun destroyed blood samples after he was visited by testers last year.

After taking bronze behind Milak, South Africa's Chad le Clos weighed in as the sample-smashing row rumbled on.

"They should all be banned for life, the guys that have cheated," he sniffed. "What Duncan did was fantastic."

Sun has yet to address the subject but the 27-year-old admitted a pile-up of races had taken its toll.

"I was exhausted," winced the Chinese idol. "My legs and arms felt sore -- the hardest part is juggling a tight schedule but I'll have to do that at the 2020 Tokyo Olympics."

An 11-time world champion, Sun accused Horton of "disrespecting China" by refusing to step onto the podium for the winner's national anthem after the 400m final at the weekend.

And Sun, who has complained privately of being shunned by other athletes in Korea, went eyeball to eyeball with Scott after Tuesday's 200m medal presentation.

The Briton ignored Sun's offer of a handshake and would not join him on the top step for photos, sparking a fiery reaction from the Chinese star.

He wagged his finger in Scott's face and yelled: "You loser, I win!"

Both men received formal warnings from FINA, as did Horton, but several athletes have come out in support of their silent protests.

Great move

Le Clos added: "He respected the podium, didn't shake his hand and I respect that. Great move by him."

Horton called Sun a "drug cheat" at the 2016 Rio Olympics in reference to a three-month ban Sun had previously served for taking a stimulant he has always maintained was approved medication for a heart problem.

The Australian reignited their war of words with his snub at the weekend, prompting Chinese state-run media to brand him a "clown" and online trolls to leave death threats on his social media accounts.

Meanwhile, Milak stormed to gold in the men's 200m fly, clocking a blistering 1:50.73 to obliterate Phelps's 10-year-old mark by almost eight tenths.

"It's a tremendous honour to beat such a great record," said the 19-year-old, who was in elementary school when American legend Phelps went 1:51.51 at the 2009 world championships in Rome.

"Everyone will try to catch me, but I will be ready."

Elsewhere, Italian Federica Pellegrini retained her 200m freestyle title in 1:54.22, while Britain's Adam Peaty completed an unprecedented hat-trick of world doubles in the 50 and 100m breaststroke as he romped to gold in the one-lap final in 26.06.

The 24-year-old, who smashed his own 100m world record earlier this week, also helped Britain to bronze in the mixed 4x100m medley relay. 

Cate Campbell blew past American Simone Manuel with an extraordinary anchor leg to bring Australia gold in 3:39.08.

"I feel like a bear who's been in hibernation," said Campbell after two days off.

"I was starting to get a little bit restless -- there are only so many episodes of 'Friends' I can watch." — AFP