The 19-year-old shuttler stunned India’s top player PV Sindhu in straight games 21-16, 21-12 in the season-ending tournament on the resort island.

“I’m very happy to successfully score a hattrick here. This victory is an upgrade for my achievements,” An said after the match.

In the men’s singles, reigning Olympic champion Viktor Axelsen of Denmark beat Thailand’s Kunlavut Vitidsarn 21-12, 21-8 in the final.

Axelsen, who was recently crowned world No 1, also won the Open title last week.

In the men’s doubles, home favourites Kevin Sanjaya and Marcus Gideon failed to follow their success at the Open after losing to Japan’s Takuro Hoki and Yugo Kobayashi 16-21, 21-13, 17-21.

This is the second loss for the world’s top pair — known affectionately by fans as The Minions — to the Japanese duo, who also beat them in the final of the Masters last month.

Japan’s women’s doubles pair Nami Matsuyama and Chiharu Shida failed to complete their clean sweep of season-ending titles after losing to South Korea’s Kim Soyeong and Kong Heeyong 21-14, 21-14 in a 44-minute match.

The Japanese pair previously bagged both the Indonesia Masters and Open titles.

“I am disappointed by this result. We were not able to get out from their pressure although we have tried to stop their domination,” Shida said.

The World Tour Finals, the last of three consecutive tournaments at the end of the season, was held amid criticism from fans who were concerned over the athletes’ wellbeing after back-to-back tournaments.

Four players including former world champion Kento Momota dropped out early due to injury.