The Springbok Sevens side beat Argentina 24-5 in the Cup quarter-final of the Las Vegas leg of the series.
Paul Treu’s men had earlier easily negotiated France’s challenge in the final pool match, winning 33-5. They then made light work of the South Americans, Steven Hunt, Cecil Afrika, Kyle Brown and Branco du Preez all scoring to set up a semi-final against New Zealand.
In the other Cup quarter-finals Samoa beat Kenya 19-14, New Zealand beat England 12-7 and Fiji downed Wales 12-5.
Click here for a full list of results from day two.