Electing to bat, South Africa posted 277 before being all out with five deliveries left in their innings.

Matthew Breetzke (88) and Tristan Stubbs (74) smashed half-centuries, and South Africa looked poised to cross the 300-mark at one stage.

Not that it really mattered, as Ngidi (5-42) and his bowling colleagues bundled out Australia for 193 in 37.4 overs to clinch the series with a match to spare.

Josh Inglis made 87 for Australia, who folded for a sub-200 total for the fourth time in a row in home ODIs.

Earlier, South Africa captain Temba Bavuma was rested as part of his workload management after a hamstring strain in June.

Aiden Markram took over the captaincy but could not lead by example and fell for a duck in the second over after electing to bat first.

Xavier Bartlett claimed a second wicket when he had Ryan Rickelton caught behind in the sixth over.

Breetzke hit Aaron Hardie for two sixes and a four in the bowler’s first over and added 67 runs with Tony de Zorzi (38) to steady the innings.

Adam Zampa (3-63) broke the stand in the 16th over when the spinner took a return catch from de Zorzi.

Nathan Ellis dismissed Breetzke and Dewald Brevis, but South Africa, at 233-5 in 40 overs and with two set batters in the middle, still looked in a perfect position for a late flourish.

Australia fought back superbly in the final 10 overs, claiming the last five wickets, conceding only 44 runs.

Cameron Green equalled an Australian ODI record for a non-wicketkeeper taking four catches.

Australia, who won the preceding T20 series between the sides, lost opener Travis Head and number three Marnus Labuschagne inside four overs.

It could have been even worse for them, but Stubbs spilled Green in the slips and Australia captain Mitchell Marsh at cover.

Marsh could not make the most of the reprieve, though and fell for 18, but Green (35) and Inglis soldiered on.

Senuran Muthusamy took a return catch from Green to break the partnership, and Ngidi effectively sealed the match when he had Inglis caught behind in the 36th over.

The teams stay put in Mackay for Sunday’s dead rubber.