Unseeded South Korean Heo Kwang-hee beat Momota 21-15, 21-19, ending the favourite’s bid for the gold medal after just two games.

Momota was appearing in his first Olympics, having been banned for gambling in an illegal casino just months before the 2016 Rio Games.

He was almost forced to retire last year after a car crash that left him with career-threatening injuries.

Momota won a record 11 titles in 2019, losing just six of the 73 matches he played that year.

But his bid for Olympic gold on home soil ended quickly, with Heo sinking his hopes in just 52 minutes.

Momota smiled incredulously as his shots failed to find their range early in the game, but looked ashen-faced when it became clear that he was in serious danger.

He sealed his own fate when he hit the net to end the match.

Momota’s early exit follows similar upsets for high-profile Japanese athletes, including tennis player Osaka and gymnast Kohei Uchimura.