Gold medalist Sun Yang of China celebrates after the men's 200m freestyle final at the Gwangju 2019 FINA World Championships in Gwangju, South Korea, July 23, 2019. (Xinhua/Tao Xiyi)

GWANGJU, South Korea, July 23 (Xinhua) -- China's triple Olympic champion Sun Yang retained his 200m freestyle world title, snatching his second gold medal at the 18th FINA World Championships here on Tuesday.

Sun clocked 1:44.93 to touch home first in the final. He was followed by Katsuhiro Matsumoto of Japan, who took the silver medal in 1:45.22.

Martin Malyutin of Russia and Duncan Scott of Britain tied for the bronze with a time of 1:45.63. Dana Rapsys of Lithuania completed the course first, but was disqualified for a false start.

"It is the first time for me to experience such a thing, also the luckiest time for me. But I think the luck came after I have done what I should do," said the winner Sun.

"After the 800m freestyle heats in the morning, my muscle is not in a good condition. And I'm the only one from the 800m freestyle event to compete in tonight's race," said Sun.

It was the second gold medal for Sun in Gwangju after he claimed his fourth consecutive world title in the men's 400 freestyle on Sunday. Sun will hunt for his third gold medal of the championships in the men's 800m freestyle final on Wednesday evening.

Gold medalist Xu Jiayu of China celebrates after the men's 100m backstroke final at the Gwangju 2019 FINA World Championships in Gwangju, South Korea, July 23, 2019. (Xinhua/Wang Jingqiang)

Defending champion Xu Jiayu added another gold medal for team China in the men's 100m backstroke. Xu won the final in 52.43 seconds, followed by Evgeny Rylov of Russia in 52.67 and Mitchel Larkin of Australia in third place.

"I really hope I can have an excellent result in these important international events, winning honor for my country and for myself," said Xu.

The 23-year-old Xu won his first 100m backstroke world title in Budapest two years ago, after taking a silver medal in the event at the 2016 Rio Olympic Games.

Ryan Murphy of the United States, winner in the Rio Games, finished fourth, failing to reach the medal podium.

Bronze medalist Wang Jianjiahe of China reacts after the women's 1500m freestyle final at the Gwangju 2019 FINA World Championships in Gwangju, South Korea, July 23, 2019. (Xinhua/Bai Xuefei)

Chinese teenager Wang Jianjiahe won a bronze medal in the women's 1,500m freestyle. The 17-year-old, who took a gold medal in the 2018 Asian Games in the same distance, clocked 15:51.00 to claim her first medal in the worlds.

Simona Quadarella of Italy took the gold medal, finishing in 15:40.89 for her first world championships title, followed by Sarah Kohler of Germany who timed in 15:48.83 to take the silver medal.

The biggest favorite, Katie Ledecky of the United States, withdrew from the final, after recording the fastest qualifying time in heats.

The five-time Olympic champion pulled out of the 200m freestyle heats earlier in the day for an unspecified ailment.

In the women's 200m semifinals, Federica Pellegrini of Italy finished first in 1:55.14, followed by Australian teenager Ariarne Titmus who defeated Ledecky in the 400m freestyle to prevent the U.S. swimmer from capturing her fourth consecutive world title in the event.

Kylie Masse of Canada got the gold medal in the women's 100m backstroke. Minna Atherton of Australia won the silver, and Olivia Smoliga of the United States came away with the bronze.

Double Olympic winner Lilly King of the United States got the gold medal in the women's 100m breaststroke. Yuliya Efimova of Russia and Martina Carraro of Italy secured silver and bronze medals each.

In the women's 20m high diving, which was introduced into the biennial championships in 2013, defending champion Rhiannan Iffland of Australia snapped up a gold medal.

Adriana Jimenez of Mexico won the silver, and Jessica Macaulay of Britain took the bronze among 12 competitors.