Daegu - Escaping a near disastrous rookie error, LJ van Zyl sneaked through the men's 400m hurdles semi-finals at the IAAF World Championships in Daegu, South Korea, on Tuesday.
Van Zyl will join Cornel Fredericks, who produced a more convincing performance in the penultimate round, in Thursday afternoon's final.
The SA record holder finished second behind former world champion Bershawn Jackson of the United States, clocking 49.05 seconds to progress automatically.
Van Zyl, however, eased up at the line, and narrowly held off Russia's Aleksandr Derevyagin, in the lane outside him, by a fraction of a second.
Had Van Zyl finished 0.03 seconds slower, he would have been eliminated.
Fredericks, 21, progressed far more comfortably, finishing second in his heat in 48.83 as the third fastest of the qualifiers.
Wenda Theron, who admitted she was "dead" tired after setting a personal best in the heats, was eliminated in the semifinals of the women's 400m hurdles.
Theron placed eighth and last in her semifinal, clocking 57.06, almost a second slower than the qualifying time she set earlier in the week.
No South African athletes will be in action on Wednesday, without any entrants in the women's 20km walk, the only event on the schedule for the fifth day of competition.