The time, run in light rain with a −0.3 wind, is a personal best and a Thai national record. It matches Xie Zhenye’s continental mark from 2019. Puripol becomes only the third Asian man to break 20 seconds.
Youwen Huang of China took silver in 20.45. Japan’s Soshi Mizukubo won bronze in 20.56.
Puripol, 20, had already won the 100m on Friday in a Games record 9.90. He ran 20.10 in Saturday’s 200m semi-finals and said Xie’s 19.88 was the target. From lane eight he was never challenged and finished more than half a second clear of Huang.
He is only the second Thai to win Asian Games 200m gold, after Anat Ratanapol. Thailand’s last title in the event was 1974.
The double follows a 100m silver at Hangzhou 2022. Two golds in Nagoya confirm him as the outstanding sprinter of these Games and put the Asian record in Thai colours for the first time.