Cape Town - Wayde van Niekerk was the quickest over the first 200m of all three 400m semi-finals, and that was enough to help him go all the way to the line and secure a spot in the final at the world athletics championships on Thursday morning (SA time).
The 30-year-old world-record holder ran 20.97 seconds over the first half lap, and was able to finish the race in 44.75 in Eugene, Oregon in the Wednesday evening session at Hayward Field.
Van Niekerk was caught over the last few metres by American star Champion Allison, who won the semi-final in 44.71.
But that won't matter to Van Niekerk, who advanced to his first major championship final since the 2017 worlds, having crashed out in the semi-finals of last year's Tokyo Olympics.
The South African managed to hold off the fast-finishing Jonathan Jones of Barbados, who clocked 44.78, to claim the second automatic qualifying position - although Jones also made it to the final as a 'fastest loser'.
American favourite Michael Norman was the quickest across the semi-finals with 44.30, ahead of Britain's Matthew Hudson-Smith in 44.38.
Former Olympic champion Kirani James won his race in 44.74, so it is sure to be a titanic battle in Friday's final (Saturday 4.35am SA time).
The other SA athlete, Zakithi Nene, finished fourth in 45.24 in his semi-final and missed out on the final.
Van Niekerk will be delighted to have just qualified for the decider considering his injury ordeals over the last few years.
To fight for a medal, though, he will have to improve considerably on his season's best of 44.58.
In the women's 5 000m heat, Caster Semenya battled as expected and finished 13th in a time of 15:46.12, having received a special invite after failing to qualify.
Zeney van der Walt clocked a new personal best of 54.81 to finish fourth in her 400m hurdles heat, but it was not enough to go through to the final.
In the women's javelin, Jo-Ane van Dyk's best effort of 57.79m didn't get her into the final either, while Tshepo Tshite finished sixth in his men's 800m heat in 1:47.61.
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