By Peter Rutherford
GWANGJU, South Korea (Reuters) - Triple Olympic champion Sun Yang accused rival Mack Horton of disrespecting China on Sunday after the Australian refused to take the podium following their 400 meters freestyle clash at the world championships in Gwangju.
The controversy overshadowed an incredible night in the pool, where Briton Adam Peaty became the first to swim the 100m breaststroke in under 57 seconds and Australian teen Ariarne Titmus ended Katie Ledecky's reign in the 400m freestyle.
Peaty has been hammering away at the 'Magic 57' mark over the last couple of years, setting a world record of 57.10 in Glasgow in 2018, and while he was confident he could always go lower even he was stunned at swimming 56.88 in the semi-finals.
"It feels incredible. I've been chasing that for three years now, ever since I touched the wall in Rio I knew I could go faster," he said.
He was careful not to get carried away, however, with the small matter of Monday's final still to take care of.
"I've come here to win a world title and that's tomorrow and that's still my main focus, so this was just a bonus and I'll use this energy tomorrow," he added.
Ledecky had been aiming for a fourth straight world title in the 400m and everything looked to be going according to plan as she powered into the lead, only for Titmus to claw back the deficit and hit the front over the final 50.
"To be honest, I kind of thought to myself just hang in there but she's going to have more and you're not going to get her, then suddenly I just felt something," said the 18-year-old Australian.
The defeat would only make it harder to beat the American at next year's Tokyo Olympics, said Titmus, who came home in 3:58.76 -- 1.21 seconds ahead of Ledecky.
"I know she’ll be back, she’s the greatest ever so this isn't going to bother her. I think it’s probably going to drive her to train harder and next year there will a real battle."
Ledecky, who still has the 200, 800 and 1,500m ahead of her in Gwangju, was stunned by the defeat.
"This stings a little, it's not what I'm not used to," she said.
"I felt like I stayed pretty calm through the race and again when I made I move she responded and when I tightened up she ran me right down.
"I'll rebound off of this and get focused on my next races."
Australia's women delivered a world championships record of 3:30.21 in the 4x100m freestyle relay to win gold ahead of the United States and Canada, while the Americans won the men's race ahead of Russia and Australia.
But the main drama came after the men's 400m, where the bad blood that has been simmering between Sun and Horton since the 2016 Olympics spilled over at the medal ceremony.
Sun, competing in South Korea despite the Court of Arbitration for Sport (CAS) set to hear a doping case against him, won a record fourth straight 400m crown with Horton, who beat him to the title at the Games, in second place.
The Australian, who labeled Sun a "drug cheat" ahead of that Rio final, stood motionless behind the runners-up spot at the podium, while Sun stepped forward to collect a 10th gold medal at the worlds and Italian Gabriele Detti picked up the bronze.
"I was aware that the Australian athlete had dissatisfaction and personal feelings toward me," Sun 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."
Horton, who also kept Sun at arm's length as they posed for photographs with their medals, did not want to get drawn into another war of words.
"His actions and I guess how it's been handled speak louder than anything I'll ever say," he said.
(Additional reporting by Joori Roh; Editing by Christian Radnedge)