Japanese teenager Shin Ohashi smashed the men's 200m breaststroke world record at the Asian Games on Thursday, setting a new mark of 2min 04.83sec.
The 17-year-old cut more than half a second off the previous mark of 2:05.48 held by China's Qin Haiyang.
Qin's record had stood since July 2023.
Ohashi had already won the 100m breaststroke gold this week in Tokyo after a dead heat with China's Dong Zhihao.
"My target has always been to break the world record and I'm so happy to have done it," said Ohashi.
"A lot happened before this competition but a lot of people helped me get to this point and I am very grateful to them.
Ohashi finished 3.84sec faster than silver medallist Denis Petrashov of Kyrgyzstan.
The Japanese teen took control from the off and from then it was a race against the clock.
He will now be the man to beat at the Los Angeles Olympics in two years' time.
"My next goal is to win gold at next year's world championships and then go on to win gold at the Olympics," he said.
"I don't want to be satisfied and I want to feel these emotions again."
Previous world record holder Qin did not swim the 200m at this year's Asian Games.