Trailing the Argentineans late in the game, coach Heyneke Meyer made radical changes that saw the Boks emerging 33-31 victors over the South Americans to put pressure on current holders New Zealand who had earlier drubbed Australia 51-20.
The win meant that South Africa leaped to the summit of the overall standings closely followed by the All Blacks.
On Saturday, with 20 minutes to go, the home team led 28-16 but late tries in the final quarter by right wing Cornal Hendricks and replacement flank Marcell Coetzee swung the tide in the Springboks favor. A late penalty goal by replacement fly half Morne Steyn was the difference in the end.
Meyer was full of praise for the replacements and testified they had shown great character to pull this one through.
The Championship will now take a two weeks break before resuming with the eagerly anticipated clash between the Springboks and Australia.