The 22-year-old Korean, seeking to regain the title he won in 2015, finished as joint-top qualifier among the 20 men who will go forward from the original field of 152 to tomorrow’s semi-finals and finals at the city’s iconic Olympic Stadium, where the 1972 Games were hosted.

Three of Chon’s six closest challengers in the qualifying are from Japan – Kokoro Fujii finished level with him, while Yoshiyuki Ogata was joint-third with Russia’s Aleksei Rubtsov, who kept his podium hopes in healthy shape for both competitions in an event that incorporates the European Championships.

Jan Hojer of Germany finished joint fifth with Japan’s Tomoa Narasaki. 

Great Britain’s Shauna Coxsey, who made certain of her overall World Cup title in winning her fourth event of the season at Navi Mumbai, India, in June, eased through to the women’s semi-finals in joint-fifth place with Akiyo Noguchi of Japan.

Slovenia’s prodigious 18-year-old Janja Garnbret, winner of last year’s lead and combined World Cup titles, strengthened her chances of a medal by qualifying equal top with Japan’s Miho Nonako, winner in Munich last year.

Coxsey’s compatriot Michaela Tracy was joint-third best qualifier along with Stasa Gejo of Serbia.