Swimming Worlds: Sun wins 400, Horton refuses podium

Sun Yang claimed a record fourth straight 400 metres freestyle title at the world championships on Sunday but the bitterness over the Chinese swimmer's doping record spilled over to the medal ceremony as runner-up Mack Horton refused to take the podium.

Touching home in a time of 3:42.44, Sun held off a storming swim from Olympic champion Horton, who had failed to even qualify for the event at the Australian trials but was added to the squad as a discretionary pick.

Horton, who has had a very public feud with Sun, labelling him a "drug cheat" before beating him in the Rio final in 2016, came home just 0.73 behind the Chinese, with Italy's Gabriele Detti third in 3:43.23.

Sun was cleared by a FINA doping panel of breaching the governing body's rules earlier this year but the World Anti-Doping Agency is seeking to overturn the decision at the Court of Arbitration for Sport (CAS).

Australia's Daily Telegraph last week posted a 59-page report by the FINA panel following a hearing at which Sun admitted to refusing to comply with an out-of-competition test because of his doubts over testers' accreditation.

Sun's lawyers have said he has asked CAS to give him the opportunity to clear his name by way of a public hearing.

Sun, who also served a three-month suspension for testing positive to a banned substance in 2014, said Horton's behaviour at the ceremony was uncalled for.

"I was aware that the Australian athlete had dissatisfaction and personal feelings towards me," he told a news conference.

"But it was unfortunate because disrespecting me is okay, but disrespecting China was very unfortunate and I felt sorry about that.

"I am aware that I have fans here and also people who don't like me, but I was just very satisfied to win today's event."

Horton made his feelings perfectly clear at the prize giving ceremony and then kept his distance from Sun as the three medallists posed for photos beside the pool.

Horton then wrapped his arm around Detti's shoulders while Sun moved off to the side to pose with his gold medal.

"Frustration. I think you know in what respect," said Horton.

"I think you know what the rivalry is like.

"His actions and I guess how it’s been handled speak louder than anything I‘ll ever say.”

Sun's victory is sure to infuriate critics of the triple Olympic champion, whose career hangs in the balance over the doping case pending at sport's highest tribunal.

But while his presence at these championships has left a sour taste in fellow competitors' mouths, the 27-year-old did not seem fazed by the controversy as he claimed a 10th world title.

Two years ago he had tied Australian great Ian Thorpe by winning his third 400 title in Budapest and he took sole possession of the record with Sunday's victory.

"I’m very happy to win this event for the fourth time in a row and I’m very proud of myself," said Sun. "I think this has been the greatest achievement in history for the Chinese team ... so I’m very satisfied."

Sun will also try to defend his 200m title on Tuesday before attempting to wrest back the 800 and 1,500 crowns later in the week, though he is no longer a force at the longer distances.

Briton Peaty breaks 100 metres breaststroke world record

Britain's Adam Peaty became the first to swim the 100 metres breaststroke in under 57 seconds on Sunday, setting a world record of 56.88 in the semi-finals of the world championships in Gwangju, South Korea.

The Olympic champion, who is unbeaten in the event over the last five years at major championships, lowered his own mark of 57.10 set in Glasgow last year.

Titmus stuns Ledecky to win 400 freestyle world title

Australian teen Ariarne Titmus shocked Olympic champion Katie Ledecky to win the 400 metres freestyle title at the world championships in Gwangju on Sunday.

The 18-year-old came home in a time of 3:58.76 ahead of Ledecky (3:59.97), who had been gunning for a fourth straight world crown in the event, with Leah Smith in third (4:01.29).