Thailand's Kunlavut Vitidsarn fought back to defeat Japan's Kodai Naraoka 19-21, 21-18, 21-7 in the men's singles final at the world badminton championships on Sunday.
After taking a close second game, third-seeded Kunlavut raced out to a 10-1 lead against a tiring fourth-seeded Naraoka in the third in a battle of 22-year-olds that took nearly 2 hours on the final day of the championships in Copenhagen.
Kunlavut also defeated Naraoka in the final of the 2018 world junior championships.
"The second game could have gone either way, and it can't be helped," Naraoka said. "Overall, I'm happy to earn the silver medal."
Naraoka was bidding to become the second Japanese player to win the men's singles title at the world championships, after Kento Momota won in 2018 and 2019.
In the women's singles final, South Korea's An Se-young trounced Spain's Carolina Marin 21-12, 21-10.
Marin had reached the final on Saturday with a 23-21, 21-13 semifinal win over two-time world champion Akane Yamaguchi of Japan.