Wales beat the Boks in a thriller at the 2006 Melbourne Commonwealth Games, but just missed out on a repeat victory. South Africa scored first, thanks to a cross-field run by Renfred Dazel, whose inside flick sent Antonius Verhoeven over for the try.
Wales hit back almost immediately when Rhodri McAtee caught the defence napping and ran around the touchline to equal the scores. Springbok star Fabian Juries exploited a gap in the Wales defence and sprang through for a 60 metre run before offloading for Tobela Mdaka to score.
In the second half, Mzwandile Stick collected a difficult ball that was toed to him, chipped and collected to put the Boks 14 points ahead.
Wales were not finished, however, with Tal Selley first bumping off Stick to put Wayne Evans away for the try. Gareth Chapman brought back memories of the Welsh fightback in Melbourne with a late try but the Boks held on for the victory.
Wales will play Portugal again in Sunday's Plate quarter-finals.