Simbine won his 100m semi-final in 9.82 seconds and although he had the benefit of a +2.8m/s tailwind, he proved his five-year-old national record was in danger ahead of Friday's final.

“I’m very excited by this result. I've been working towards this for a long time,” Simbine said. “Even though it’s wind-assisted, it shows I have it in the legs and my body can go this fast. It's about trying to put together the perfect race and getting my phases right. If I do that, anything can happen and the times will come.”

Gift Leotlela, a former 200m silver medallist at the World Athletics U20 Championships, also delivered a superb performance, clocking 9.94 to win his semi-final with a +3.6m/s wind.

Rocco van Rooyen launched a massive 85.25m heave to win the men's javelin throw final.

Johann Grobler, another former medallist at the World Athletics U20 Championships, also did well to send the javelin beyond the 80m mark. He earned the silver medal with a throw of 80.32m.

Earlier in the day, two-time Olympic 800m champion Caster Semenya successfully defended her national 5 000m title in 15:52.28. Semenya, who is aiming to achieve the qualifying standard of 15:10.00 for the Tokyo Olympics this season, held off a challenge from Athletics Gauteng North teammate Glenrose Xaba who took second place in 15:55.25.

“I'm happy with how the race went today and with where we are at the moment. I'm not focussing on Tokyo yet. We're still building up to that. We will try for the qualifying time when the time is right and if it comes then it comes, but for me right now it's about having fun,’ said Semenya.

In other events, 2013 World Athletics Championships finalist Victor Hogan secured victory in the men's discus throw final with a best attempt of 61.25m, well ahead of the rest of the field.

After breaking the SA junior women's shot put record last week at the ASA Age Category (u16-u20) Championship in Paarl, Mine de Klerk built on her impressive form by earning the national senior title.

De Klerk won gold with a best effort of 16.82m, with Ischke Senekal taking second place (16.58m) and Meike Strydom grabbing bronze (16.21m) in a hard-fought battle. Mbuleli Mathanga gradually drew clear in the latter stages of the men's 10 000m race to secure victory in 29:23.74.

Yvonne Robson won gold in the women's high jump final, sailing over the bar at 1.80m.

Producing perhaps the biggest upset of the day, Jo Ane van Dyk won the women's javelin throw final with a 59.47m heave, edging Olympic silver medallist Sunette Viljoen into second place (57.37m).

“The blistering performances we witnessed captured the Day 1 of the competition as was expected, with some walking away with titles and some reaching the semi-final and finals in their events.

“We congratulate the winners of the day and those have progressed to the next stage in the events. We must not forget to thank the coaches of this country who have managed to keep their athletes in the best of shapes despite the challenges that the global pandemic has caused,” said Aleck Skhosana, the President of Athletics South Africa.