Australia has lost to South Africa by 32 runs in their second ODI clash of the series, with the Aussie middle order collapsing.
Adam Zampa went for 0-77 from his 10 overs and Josh Hazlewood went at seven runs an over while claiming three wickets.
Australia and South Africa will play the third ODI in the series at Potchefstroom on Wednesday night (AEST).
Australia's world champions have been found wanting again, falling well short in a chase for the second time in four days as South Africa prevailed by 32 runs in Johannesburg to seal the three-match ODI series triumph.
As a reconnaissance mission for their World Cup defence in southern Africa in a year's time, the loss overnight felt like another capitulation after a fine start to their pursuit of a big Proteas total was wasted, just as on Thursday in the first-match collapse at Durban.
Chasing South Africa's formidable 9-365, which featured hundreds from captain Temba Bavuma and the ever-reliable David Miller, Australia's stand-in skipper Mitch Marsh and Travis Head, who had teed off with a brisk 90 together in Durban, this time clattered 130 off 17 overs at the Wanderers.
But the same old failings of cheap dismissals and inability to build partnerships came back to haunt the visitors, with not even a rousing late show of defiance from Xavier Bartlett, with a thumping 50 off 28 balls, able to get them to within a sniff of the target as they succumbed to 333 all out with one ball remaining.
After losing a second-straight match in which they had won the toss and sent the Proteas in, Australia, who again kept captain Pat Cummins on ice with the Test series around the corner, were left with further big concerns over their middle order stuttering in the face of quality spin.
"Really disappointing — we came here to ensure the series went to the last game but, fair play to South Africa, ultimately we've been outplayed again," Marsh said.
"In both games, the way we've set up the innings has been good but we just haven't been able to execute in those middle phases.
"We've got to keep improving, we don't want to be whitewashed."
A third match will be played in Potchefstroom on Wednesday.
Cummins was missed and a side injury that ensured Australia's quick Nathan Ellis could bowl only four overs meant their attack was always under pressure, even if Jack Edwards offered genuine all-round promise with his 5-67 and a solid knock of 25 in support of Bartlett.
Josh Hazlewood took three wickets while going at seven an over, but more alarming was Adam Zampa's continuing struggle, as he went for 0-77 off his 10 overs, in contrast to South Africa's spin trio of Keshav Maharaj (2-54), Bjorn Fortuin (2-70) and Aiden Markram (1-55).
They helped put the brakes on Australia's chase after Marsh and Head had cracked 84 apiece, the captain's knock featuring five sixes and 10 fours off 53 balls and Head's start coming off 103 balls, with one six and 12 fours.
Apart from the openers, though, Australia was soon struggling, Cooper Connolly chipping one tamely off Lizaad Williams (3-54) to short midwicket to depart for 10 and wicketkeeper Alex Carey trapped lbw by Maharaj, who then did the same to dismiss Matt Renshaw for 32.
Cameron Green had a struggle, limping to 17 off 34 balls, before Bartlett showed him the way with his five mighty sixes, only for his innings, and Australia's last hope, to be ended by a cracking leg-before yorker from Williams.