The scoreline didn't reflect the toughness of the contest, which saw the Diamonds tested by a strong Proteas defence that rarely relented from the first whistle.
Caitlin Thwaites was again flawless under the post, shooting 15 goals from 15 attempts to take her tournament tally to 75/75, with her combination with goal attack Steph Wood the spark that broke the game open in the third quarter.
Wood finished with 14/15 and four assists before leaving the court in the shadows of full-time with a blood nose.
South Africa fared worse on the injury front, with Queensland Firebirds midcourter Erin Burger suffering a dislocated finger and Precious Mthembu crashing to the court early in the second half with a knee injury. She had to be assisted from the court and could not return.
Coach Lisa Alexander again made full use of her squad's depth, with Caitlin Bassett, Laura Geitz, April Brandley, Susan Pettitt, Kim Ravaillion, Madi Robinson and Gabi Simpson in the starting seven and all positions rotated heavily throughout the contest. No starting seven has been the same during the tournament.
The Proteas fired early, staying within four goals for much of the first quarter.
A brilliant defensive effort from Simpson yielded two intercepts - one leading to a goal - and three deflections, while Brandley was also involved heavily early, with two deflections and an intercept.
A couple of late goals from Bassett handed Australia a 16-9 first-quarter advantage, but South Africa was well in the contest.
Simpson kept producing in the second quarter, with the only thing stopping her - albeit briefly - being some friendly fire when she hit the deck after a collision with Geitz. The Diamonds took a 30-21 lead into the main break.
Thwaites, Courtney Bruce, Liz Watson, Jo Weston and Wood were brought into the fray to start the third quarter, as the Diamonds again looked to push their advantage.
In a stunning show of toughness, Burger's dislocated finger early in quarter - which stuck out at a right angle - was put back in place and she returned to the court soon afterwards. The fate appeared more serious for Mthembu, who crashed to the floor with a knee injury seconds later.
It was those injuries that opened the window for the Diamonds, who broke the game open with a Wood-led 8-1 run that paved the way for a 45-29 third quarter lead, which they extended further with a 15-9 final term.
Australia next plays Fiji at 3pm AEST on Monday before a showdown against Jamaica on Wednesday at 9pm AEST.
