Commonwealth Games bronze medallist Ryan Coetzee and Ayrton Sweeney added their names to the list of Fina World Long-Course Championships qualifiers on Wednesday.
Coetzee secured his place for the global showpiece during the morning heats of the 100m butterfly, posting a time of 51.85 seconds at the SA championships in Durban.
He could not repeat the performance during the final at Kings Park, with four-time Olympic medallist Chad le Clos winning in a qualifying time of 51.39.
Le Clos was the first male swimmer to book his place for the world championships in Gwangju, South Korea in July, when he qualified in the 200m butterfly on Monday evening.
Sweeney was in a class of his own in the 400m individual medley, smashing into the wall first in a qualifying time of 4:17.67, which is 0.23 seconds under the required mark.