The 24-year-old finished in 43.03 seconds, 0.15 quicker than the time Johnson clocked in Seville in 1999.

According to BBC, Grenada's Kirani James, the London 2012 champion, finished 0.73 behind to take the silver medal, with American LaShawn Merritt in bronze.

Van Niekerk's earlier runs in Rio gave little indication of what was to come.

He beat James and Merritt at the World Championships in Beijing last year, with all three going under 44 seconds, but qualified fifth fastest for the final.

James set off fast at the start of the race, but Van Niekerk, in lane eight, powered around the final bend to beat his previous personal best by 0.45. BBC reports.

Not only was it his first Olympic medal, he also became the first man to win an Olympic 400m title from lane eight.