Annabelle Lindsay set the tone, scoring the first six points of the game and ten of Australia's first 12.
She almost had a double-double by quarter-time, absolutely stuffing the stat-sheet with 16 points, nine rebounds, two assists, two steals and two blocks as the Devils assumed control of the contest.
Maryanne Latu played a crucial role in the first quarter as well, recording three assists to help the Devils to a 24-8 lead.
The second term saw Lindsay continue her domination, officially recording a double-double while Jess Cronje and Georgia Bishop-Cash came off the bench to crash the glass and get on the scoreboard as well.
South Africa had the opening basket of the second period but from there, the Devils went into half-time on a 16-0 run to take a 30-point lead.
Australia's defence was exceptional in the second half, keeping South Africa scoreless in the third term and holding them to just two points in the final period.
That enabled coach Stephen Charlton to rotate through his second unit as nine players hit the scoreboard including Sarah King (four points, three rebounds) and Lauren Hardbottle (two points, one rebound).
Bishop-Cash (14 points, 13 boards, four assists) and Cronje (ten points, ten rebounds) went on to record double-doubles while Lindsay completed an unbelievable performance.
In just 19 minutes, she out-scored South Africa by herself and almost out-rebounded them with 32 points, 24 rebounds, three assists, two steals and two blocks.
"We got everyone a chance to hit the floor, everyone came through healthy and most importantly we played the game we wanted to," said Devils head coach Stephen Charlton.
Find the box score here and watch the replay below.
The Devils will now play the winner of Great Britain vs. Turkey which tips off at 8.15pm tonight. Great Britain were undefeated through the group stage, winning by an average margin of 49 points.
"It looks like we'll face Great Britain and they will be tough but we'll put plans together this afternoon," said Charlton.
"We have some things that will trouble them through our big's and if we play Devils basketball, we can get the result we're looking for."
The Australian Devils schedule for the 2019 IWBF U25 World Championships (all times AEST):