efe-epaGwangju, South Korea

British swimmer Adam Peaty on Sunday broke his own world record in the 100-meter breast stroke with a time of 56.88 seconds at the 2019 FINA World Championships.

The 24-year-old had been the first man to reach the finish line of the 100-meter breaststroke in under 58s, when he posted a time of 57.10 seconds in Glasgow on Aug. 4, 2018.

China's Yan Zibei came second in Sunday's semifinal with a time of 58.67 seconds, a new Asian record.

These records overshadowed another achievement by Australian swimmer Ariarne Titmus, who stole the limelight for a while as she ended the domination of United States' champion Katie Ledecky in the women's 400 meter freestyle; Ledecky had won all the 400 meter since 2013.

With 50 meters to go, the 18-year-old Titmus was 0.6s behind Ledecky, but in the final stretch, the Australian managed to turn the tables.

Titmus took the gold medal home as she posted a time of 3:58.76, a new Oceania record, ahead of Ledecky, who recorded 3:59.97.

Leah Smith of the United States, meanwhile, completed the podium with a time of four minutes and 1.29s.

China's Sun Yang, by contrast, kept things under control in the men's 400 meter freestyle as he clinched the gold medal.

Yang had to overcome a bit of resistance from Australia's Jack McLoughlin, but things got easier 150 meters into the race as Yang took a more dominant position.

Yang, eventually, posted a time of 3:42.44, the record of the year in the 400 meter category, ahead of Mack Horton of Australia (3:43.17).

Gabrielle Detti took home the bronze medal as he set a new Italian record of three minutes and 43.23 seconds.

After the race, the differences between Yang and Horton emerged as the Australian refused to share the podium with the Chinese.

Horton did not pose for a picture with the winner and the bronze medalist.

Horton has been a critic of Yang regarding doping suspicions that surround the Chinese swimmer.

The Australian is the last man to defeat Yang, which happened in the 400 meter freestyle at the 2016 Olympics.

Following that race, Horton attacked Yang over failing a 2014 doping test for Trimetazidine, a steroid.

The World Anti-Doping Association (WADA) requested an investigation of Yang after the International Swimming Federation (FINA) postponed a decision because the Chinese swimmer skipped a out of competition test.

According to reports, Yang, a three-time Olympic champion and eight-time world champion, used a hammer to destroy a bottle of his own blood which had been collected by anti-doping inspectors.

This event reportedly occurred at Yang's home in September 2018.

An investigation into Yang's possible use of doping is set to start in September of this year.

The finals of men's and women's 4 x 100 freestyle wrapped up the opening day of swimming competition.

The US team of Caeleb Dressel, Blake Pieroni, Zach Appel and Adrian Nathan won the gold, a championship record included, with a time of 3:09.06, ahead of the Russians and Australians.

The women's title went to the Australia team of Bronte Campbell, Brianna Throssell, Emma McKeon and Cate Campbell, who also broke the tournament record with a time of 3:30.21.

The US team had to settle for the silver medal, while Canada came in third. EFE-EPA