China's Xu Jiayu won men's 100m backstroke gold at the world aquatics championships on Tuesday but confessed he was "disappointed" not to set a new world record.

The 21-year-old Olympic silver medallist clocked 52.44 seconds with the American duo of Matt Grevers earning silver, at 0.04sec back, and Olympic champion Ryan Murphy taking bronze at 0.15.

"My main aim is to break the world record," admitted Xu, who fell short of Murphy's record of 51.85sec set at the Rio Olympics last year.

"I'm a little disappointed not to break it, but of course I'm happy with the win."

"Sometimes it comes down to many factors, luck, or a good swim, it can be hard to say which is the greater factor.

"The silver medallist chased me really hard, it really depended on a small pinch of good luck.

"It's quite an education, last year in Rio, a silver - this year, a gold."

Having failed to qualify for the final at the 2013 world championships, Xu's star has risen in recent years.

"I got better results in 2015, each time I compete the goal is different," he said.

"I think of a new goal to achieve every time, today it was the gold medal. Further on I will work on new goals."

Grevers, 32, was delighted with his silver at his fifth world championships.

"I feel great, even a month ago if somebody said I took the silver, I would be OK with it, but now I am here," he said. "This inspires me to get back to my best.

"Xu swam really well, I knew he was gonna go fast, he was between Ryan and I and he did it."

But Murphy, the Olympic champion in both the 100m and 200m backstroke, was far from pleased to have been beaten into third.

"I am not really happy with the result. It is not so great if you are finish up as third," said the 22-year-old.

source: AFP