Japanese teenager Shin Ohashi moved closer to a hat-trick of Asian Games breaststroke golds after qualifying for the 50m final on Friday, the morning after smashing the 200m world record.
The 17-year-old clocked an astonishing 2min 04.83sec in Tokyo to slice more than half a second off the previous 200m breaststroke mark held by China's Qin Haiyang.
It was Ohashi's second gold of the Games, having won the 100m breaststroke gold after a dead heat with China's Dong Zhihao.
The world record continued Ohashi's stunning rise in the sport and marked him out as the man to beat at the 2028 Los Angeles Olympics, where he could face French superstar Leon Marchand.
Ohashi booked his place in Friday night's 50m breaststroke final in a time of 27.00sec, finishing 0.13sec behind fastest qualifier Qin.
"I felt comfortable," said Ohashi, who went down with a bout of Covid shortly before the Games began.
"But I have to get myself pumped up for the final."
Ohashi has become an overnight star in Japan, with the morning TV news shows replaying his performance.
He said he had not had time to take in his achievement.
"I replied to the messages I had and then just lay there waiting to fall asleep," he said.
"I didn't sleep much, but it was about same amount as I get when I do my usual morning practice, so I think I will be fine."
Qin did not compete in the 200m breaststroke, after taking bronze in the 100m event.
He said he had "a lot of respect" for Ohashi and expects to see more great performances.
"He's just 17 years old and he has talent," said Qin.
"I think he's a genius."
Ohashi's Japan teammate Ippei Watanabe, himself a former 200m breaststroke world record holder, was also full of praise for the teenager.
"I couldn't sleep because I was watching Ohashi's swim over and over on YouTube," said Watanabe, who finished fifth in the final.
"I probably got less sleep than he did."