Chad le Clos (Supplied)
Cape Town - Chad le Clos put the disappointment of missing out on a medal in the 200m butterfly final by easing into the semi-finals of the 100m butterfly on Thursday.
Le Clos, swimming in Heat 5 (of 6), touched the wall in third place in a time of 51.75.
Michael Phelps, aiming for his fourth gold in Rio, finished second in his heat behind Singapore's Joseph Schooling in a time of 51.60.
Le Clos' time wound up to be the seventh-quickest overall.
Schooling's 51.41 was the fastest time of the heats.
Le Clos won a silver medal in the event in London four years ago, behind Phelps.
The semi-finals will take place later on Thursday (04:34 SA time).