Despite a yellow card to star flyer Seabelo Senatla, the Blitzboks still came through their Hamilton Sevens Cup semi-final to beat Australia 24-5 at the Waikato Stadium on Sunday.
The South Africans will now take on Fiji in the final at 9.03am SA time.
In a bright start to their playoffs, the Blitzboks got past Scotland 22-0 in the quarter-finals.
But it was all to play for in the last four against the Aussies, who were ruthless in winning the Sydney Sevens last weekend in thrashing the Blitzboks 29-0 in the final.
The South Africans made a great start, with Cecil Afrika opening the scoring for a 5-0 lead.
Tim Agaba then set up the second try by winning an Australian lineout, and Werner Kok fed Senatla to go over.
But when Senatla was yellow-carded for a deliberate knockdown, the Aussies took full advantage as Timothy Anstee scored.
In a remarkable bit of play, Rosko Specman chased down Ben O'Donnell about 10 metres before the line, and after a knock-on by James Stannard, the Blitzboks went all the way as captain Kyle Brown popped the ball up for Afrika.
It was the Blitzboks' game to lose from 17-5 ahead, and they added another touchdown from Kwagga Smith in a typically belligerent solo effort as he shrugged off a number of defenders to gain sweet revenge for the Sydney final defeat, and secure their spot in the final against Fiji, who beat New Zealand 14-12.