The Blazeboks now have to beat Great Britain in their final pool match at the inaugural HSBC SVNS in Perth on Saturday to stay in the hunt for a spot in the top eight of the tournament. That match, live on SuperSport, kicks off at 05h32 (SA time).
The Bok Women were always going to be up against it against Australia, who won both tournaments in Dubai and Cape Town in front of a home crowd, but the hosts had to work hard, especially in the second half of their game.
They blitzed the South Africans in the opening two minutes to score two tries and rushed into a 12-0 lead, but once Zintle Mpupha and her troops got their hands on the ball, some parity was restored.
The Aussies scored just before the break to extend the lead to 17 and they added two more tries in the second half, but they also had to weather some good attacking play from the Bok Women.
In the second game, Canada outflanked the Blazeboks early in the match for the opening try and gained a 7-0 lead, but for the rest of the half, it was a tussle between defence and attack from both sides.
The Canadians outplayed South Africa 40-0 in their last fixture last month in Cape Town, but the 7-0 scoreline at the break was a good reflection of the pressure coming for the lower ranked side.
Canada extended their lead to 12-0 early in the second half before a delightful try by Mpupha put the South Africans within bonus point range, with four minutes to play.
The Canadians then sneaked a try with the Blazeboks an injured defender down and sealed the match with a good attacking move near the end.
Scorers:
Australia 31 (17), South Africa 0 (0)
Australia - Tries: Bienne Terita (2), Alysia Lefau-Fakaosilea, Faith Nathan, Heidi Dennis. Conversions: Teagan Levi (2), Dominque du Toit.
Canada 26 (7), South Africa 7 (0)
Canada - Tries: Krissy Scurfield (2), Charity Williams, Asia Hogan-Rochester. Conversions: Chloe Daniels (2), Hogan-Rochester.
South Africa - Try: Zintle Mpupha. Conversion: Nadine Roos.