The hosts refused to back down, however, as Marcus Stoinis (five fours, four sixes) and Shaun Marsh took their side comfortably past the 100-run mark.
South Africa captain Faf du Plessis and David Miller not only steadied the team's innings against Australia in the third and final ODI but went on to shatter a South African one-day global record on Sunday.
For South Africa, Dale Steyn and Kagiso Rabada picked up three wickets each.
South Africa were also unchanged, retaining the allrounder Dwaine Pretorius at No. 7. "From a batting point of view we were good, but from a bowling point of view we were excellent".
The Proteas' mammoth 5-320 proved out of reach for Australia on Sunday night despite a determined 106 from veteran Shaun Marsh.
South Africa take the series 2-1 in front of 5231 fans after Australia had levelled in Adelaide with a seven-run win in game two.
Du Plessis and Miller stitched together a record 252-run stand for the fourth wicket to dig out South Africa from troubled waters.
Erdogan, Trump meet over dinner in French capital
Trump added that the U.S. wants to "absolutely be there" to help defend Europe but that "different countries have to also help". Their meeting Saturday, however, included declarations of friendship but lacked their previous over-the-top displays of warmth.
After winning the toss and putting the visitors into bat, Australia got a dream start with Quinton de Kock out in the third over.
Aiden Markram smashed three sixes, including one huge blow off Marcus Stoinis that went out of the ground and down the street, with a new ball needed, on his way to 32.
Du Plessis and David Miller shared a 78-run stand before the skipper dragged Pat Cummins onto his stumps for 47.
However, Pretorius swung the game back in South Africa's favour by dismissing Marsh in the next over, when the left-hander looked to whip one towards the leg side but ended up skying it to Heinrich Klaasen at wide long-on. "Du Plessis" 114-ball innings included 15 fours and two sixes and was his 10th in global one-dayers, while Miller's vindicated his elevation up the batting order.
Earlier, South Africa were revived by centuries from du Plessis and Miller, who took them from a precarious position to well over 300.
Australia experimented with Chris Lynn as opener for the run chase, but it spectacularly backfired when Steyn snared him for a golden duck.
Miller made the landmark in 95 balls, including eight fours and two sixes, and was finally caught at deep midwicket off Josh Hazlewood in the last over.
