The Blitzboks followed their win over the USA, with a 10-07 over the host nation Australia with a late try in the second half.
The Bitzboks will face Argentina on Saturday at 07:50 in their final Pool A match.
The Blitzboks dominated the early minutes of the match and Donovan Don eventually scored in the corner. Minutes later Dewald Human dropped the ball going over for the Blitzboks' second try.
With a minute left to play Australia struck back after a fifty-meter run when James Turner scored an easy try. Australia weathered the early storm and deservedly led 07-05 at the halftime break.
The Blitzboks absorbed a lot of pressure in the first four minutes of the second half, however, disciplined defence by the Blitzboks upped the pressure on Australia and David Brits pounced on a knock by Australia to score the Blitzboks' second try. The Blitzboks led 10-07 with two minutes to play.
Scorers:
Bitzboks: Tries: Donovon Don, David Brits.
Australia: Try: James Turner. Conversion: Maurice Longbottom.
Teams:
Blitzboks: Quewin Nortje, Donavan Don, Dewald Human, David Brits, Zain Davids, Ricardo Duarttee, Impi Visser. Replacements: Ryan Oosthuizen, Siviwe Soyizwapi, Shilton van Wyk, Selvyn Davids, Ronald Brown.
Australia: Henry Hutchison, Ben Dowling, Aden Ekanayake, Jayden Blake, Michael Icey, Maurice Longbottom, James Turner. Replacements: Matthew Gonzalez, Josh Turner, Hadley Tonga, Ben Dalton, Hayden Sargeant.