Having lost the first-of-three clash earlier in the week, the Baggy Green restricted South Africa to 101 off their 20 overs and then eased through their chase to wrap up a comprehensive seven-wicket win.
Captain Aaron Finch clubbed a 30-ball 44 to do most of the damage, with other worthwhile knocks coming from Ben Dunk (23) and Shane Watson (30) as the tourists were drubbed in Melbourne.
It was never going to be much of a contest as Australia tore into their chase, making 43 before they lost their first wicket in the fifth over when Dunk went after a tone-setting contribution.
Watson joined Finch after that and they shared a stand of 49 before the former became Wayne Parnell’s second victim. Even though Glenn Maxwell managed just a two-ball duck, the job was seen through by Finch.
South Africa’s innings simply never got going, despite JP Duminy’s 49.
They got off to a shocking start as Quinton de Kock went for a second-ball duck, edging Doug Bollinger behind, and never really recovered.
Rilee Rossouw went in the next over, putting a leading edge back into the hands of bowler James Faulkner, before a promising-looking knock from Reeza Hendricks ended on 18 when Cameron Boyce tempted him down the track and Dunk stumped him.
South Africa were 46-3 at that stage and a fourth wicket went down for 60, with Boyce and Dunk combining in identical fashion to get rid of Farhaan Behardien.
David Miller remained and as such so did danger, but he was soon gone too, aiming for the boundary off Faulkner but finding the hands of Pat Cummins.
Next went Ryan McLaren – Cummins and Faulkner swapping roles – and when Duminy went a run short of his 50, Faulkner (three for 25) striking again, the game always looked up.
The series will now be decided in Sydney on Sunday.