Sunday’s final always promised to be a thrilling race but for most inside the Olympic Stadium it was merely the appetiser ahead of Usain Bolt in the 100m final.
The Jamaican’s triumph got the Brazilian crowd on their feet, but Van Niekerk left them open-mouthed.
The South African overcame Kirani James and LaShawn Merritt at last year’s World Championships and did so again in Rio de Janeiro, not only clinching gold but doing so in a world-record time of 43.03 seconds — obliterating Johnson’s run of 43.18 from 1999.
“I can’t even tell you what happened in the race,” Van Niekerk said at a packed press conference, sat alongside silver medallist James and third-placed Merritt.
“As I got to the finish line, I was expecting one of the two to catch me. I crossed the line, I look left and I saw there was no-one.
“I am still a bit amazed and I still have to pinch myself about what just happened.”
Van Niekerk’s time is made all the more remarkable by the fact his world-record run came from lane eight.
It was a performance that had his family in tears and left the 24-year-old struggling to comprehend his rapid ascent.
“It’s amazing,” said Van Niekerk, who in March became the first person to have dipped below 10 seconds in the 100m, 20 seconds in the 200m and 44 seconds in the 400m.
“I am still amazed just being here, just being amongst the great athletes.
“The last Olympics in London I was sitting at home watching all these guys doing their thing, and today I am in the mix with them and had the opportunity to run my best performance.
“I am just really grateful for being part of this generation of athletics and just keeping the sport alive.
“I am really just blessed and thankful to the Lord for this opportunity.”
Van Niekerk repeatedly thanked God in the post-race press conference and praised his coach Anna Botha, a great-grandmother with almost 50 years of coaching experience.
In this era of athletics, though, a world record — and such a stunning one at that — will naturally lead some to question whether they can believe what they are seeing.
Van Niekerk brushed off an initial question about doping but was pushed further on the subject. “I know I am not, so what else can I say on that?” was his response.
The South African’s rise to prominence certainly appears a timely boost for the sport, given Bolt is bidding farewell to the Olympics in Rio de Janeiro.
“Obviously I use these guys as an inspiration and motivation as an athlete,” Van Niekerk added.
“But, yeah, I have got the opportunity to build my own, if I can say, legacy, and my own journey and story, “Hopefully I can inspire so many more South Africans and, actually at this moment, more athletes around the world to go out and do their thing, and try and achieve as much they can.
“Thinking back to where I was four years ago, it shows anything is possible for anyone that believes.”