Johannesburg – Chad le Clos won his 400m individual medley heat to qualify for the final later on Saturday night, becoming the first South African to compete for a medal.
Swimming against American star Ryan Lochte, Le Clos touched first, in 4:12:24, an eleventh of a second ahead of Lochte, who slowed visibly towards the end.
Riaan Schoeman finished sixth, swimming in the lane next to Le Clos, and his 4:17.22 ended his Olympic campaign.
The fastest finisher was Japan's Kosuke Hagino, who clocked 4:10.01, in the third heat, while Olympic phenomenon Michael Phelps won his heat in 4:13.33.
Cameron van den Burgh was sixth fastest in the men's 100m breaststroke qualifiers, with his 59.49sec time seeing him safely into the semi-finals in the evening session.
Also in the pool on Saturday, Heerden Herman came seventh in his 400m freestyle heat, clocking 3:57.28 and he will now turn his focus to the 1500m freestyle heat on Friday.
Kathryn Meaklim finished sixth in her 400m Individual Medley heat, failing to qualify for the final. Her next event is the 200m Individual Medley on Monday.
South African rowing pair Naydene Smith and Lee-Ann Persse finished fourth out of five in the Women's Pairs second heat.
Their time of 7:14.31 earned them ninth place overall which saw them qualify for the repechage on Monday.
The fastest time was 6:57.29 British pair Helen Glover and Heather Stanning, set in the first heat.
The top two boats from each heat automatically qualified for the final while the other six boats compete in the repechage, which offers a second chance to qualify for the A final. Unsuccessful boats from the repechage go forward to final B, which determines places 7-12.
Rowing lightweight four – Matthew Brittain, Sizwe Ndlovu, John Smith and James Thompson – came second in their heat and go through to the semifinals on Sunday. – Sapa