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'.