Carina Horn, LJ van Zyl and Stephen Mokoka all came up short in their Olympic preparations at the IAAF Diamond League in London last Friday.
SA women’s 100m record holder Horn made a good start to her day when she clocked 11.15 to end fourth in her heat.
But it wasn’t enough for Horn to reach the final about an hour later.
The 27-year-old Van Zyl was up against a stellar field in his one-lap race, with the likes of Americans Johnny Dutch and Kerron Clement, as well as Javier Culson of Puerto Rico in the line-up.
Van Zyl, though, ran out of steam a bit in the last 50m to end fourth in 48.92 - which is still a good time in the sub-49 seconds.
Mokoka is entered for the 10 000m in Rio, but told Independent Media this week that he needed some top competition before going to Brazil, which is why he decided to accept the invitation for the 5000m in London.
The national champion in both long-distance events had an excellent first half of the race as he kept up with Britain’s Olympic champion Mo Farah and Kenyans Paul Koech and pacemakers Vincent Rono and Hillary Maiyo.
Mokoka faded to ninth in 13:23.66, but he will be pleased with his performance as it was part of his preparation for Rio.
The other South African in London was 400m hurdler Wenda Nel, who produced a new season’s best of 54.47 on Friday night to finish third behind American star Dalilah Muhammad (53.90) and Denmark’s Sara Petersen (54.33).