It was 3.00 pm on a Monday afternoon with a buzz around the Olympic Games Village. Athletes came and went, attending competitions and fulfilling media obligations. An Argentine triathlete relaxed in a beach chair while Kazakh athletes hesitantly checked out the beauty salon.

Then came South Africa’s Wayde van Niekerk, the reigning world record holder and the gold medallist of the 400 metre race. At first he was a multi-coloured dot in the distance, but, as he approached, he slowly unfurled into the life-sized top athlete he is, with thin, toned legs.

Wayde van Niekerk has already gone where no one else has. The 24-year-old from South Africa is the first person in history to run faster than 10 seconds over 100 metres, 20 seconds over 200 metres and 44 seconds over 400 metres. Obviously, the key question had to be put to him: what is the greatest secret of your success?

“Discipline,” he grinned. And he would know. The secret to van Niekerk’s discipline is none other than his coach, Anna Sophia Botha. At 74, Botha is possibly the coolest great-grandmother in the world. She is as unassuming and modest as one can be, notwithstanding the remarkable feat of coaching van Niekerk to Olympic gold.

Coaching glory

The septuagenarian walked next to her prodigy, slightly bewildered by the global media attention she was receiving – the New York Times and BBC were waiting for her. When van Niekerk won the gold medal in the 400 metre dash on Sunday night at the Olympic Stadium, Botha encountered comical difficulties when she tried to congratulate her ward for his outstanding achievement.

Tannie Ans (Tannie means aunt in Afrikaans) was overjoyed, but given her lustrous white hair and genteel demeanour, event officials turned her away from the venue, despite her credentials. “At every entrance there was security and they just wouldn’t let me go through,’ said Botha. Team South Africa intervened to reunite coach and athlete in the bowels of the Olympic Stadium.

“We just hugged each other,” Botha said. “It wasn’t necessary to say anything. We knew in our hearts and in our minds what we had thought and what we had achieved.” van Niekerk had clocked 43.03 seconds. Johnson’s world record, which he had set in 1999, stood at a distinct second best at 43.18 seconds.

Botha is a native of Namibia, where she competed in the sprints and the long jump, but without much distinction. In 1968, she began coaching. Rio 2016 is, however, her first Olympic Games. In 2012, van Niekerk asked her to become his coach at the University of the Free State in Bloemfontein. Botha has been the head track and field coach since 1990 at the university. At that time, van Niekerk was the South African champion at the 200 metre with a personal best of 20.57 seconds.

Never too old

Botha had the prescience to move the talented van Niekerk to the 400 metre dash, away from his favourite 200 metre race, because of his injury-prone nature. The 400 metre race would still allow van Niekerk to exploit his sprint capacity and explosiveness. At the World Championships in Beijing in 2015, her instinct was validated: van Niekerk won gold.

Botha is a disciplinarian. “In the moment when we start training,” said Botha. “I want their focus and dedication and hard work in the training. Otherwise it makes no sense to train.”

But she explained how important it was for her to remain with van Niekerk and her other athletes, on a day-to-day basis. “I have to read my athlete. I have to read his mind and read his body and listen to what his body tells me. I think I have the ability to know my athlete inside out,” she said.

Van Niekerk’s greatest asset is his personality, according to Botha. “That is the only word I can think of,” said Botha.

In the Olympic final, van Niekerk was victorious from Lane 8, the outer lane, which is considered detrimental as a blind spot, but it did not bother him. He led from the start and never relinquished first place. He did not see another runner during the race, defeating favourites Kirani James of Grenada and LaShawn Merritt of the United States.

The South African is already a speed king, but can he possibly be a successor of the enigmatic Bolt? Botha said they would plan the future when they returned to South Africa. Andre De Grasse of Canada and Meritt may be the more likely candidates.

As for Botha, who turns 75 later this year, she has no plans of retirement. “You’re never too old to learn. I still love coaching and I still love my athletes,” said Botha. “So I can’t see a reason why I would go and sit down and play with my fingers.”

(Correction and clarification: An earlier version of this story had incorrectly identified Andre Botha as Wayde van Niekerk's great-grandmother. They have no family ties. The error has been corrected.)