Faf du Plessis and David Miller both made centuries as South Africa beat Australia by 40 runs in Hobart to clinch the one-day series.
The Proteas were seeking to claim their first 50-over series in Australia since 2009, the Baggy Greens having levelled matters at 1-1 by snapping a seven-match losing streak in the second encounter in Perth.
The Aussies won the toss and put the tourists into bat, a decision they would ultimately regret, despite removing Aiden Markram (32), Reeza Hendricks (8) and Quinton de Kock (4) relatively cheaply to leave South Africa at 55-3.
Miller blasted 139 from 108 deliveries, including four sixes, while skipper Du Plessis scored 125, his 10th ODI century, as the pair shared a fourth-wicket stand of 252 runs.
South Africa eventually posted 320-5 from their innings and they were quickly into the Australia batting order, Dale Steyn removing Chris Lynn for a golden duck, while skipper Aaron Finch was dismissed for 11.
Shaun Marsh put up some resistance with a battling 106, while Marcus Stoinis (63) and Alex Carey (42) chipped in as Australia put on an improved display with the bat. However, it was ultimately futile as they finished their 50 overs at 280-9, Kagiso Rabada and Steyn taking three wickets apiece for the Proteas as they wrapped up a convincing win.
“I thought we played our best game of cricket. We challenged ourselves to put in a performance. A high pressure game. From a batting point of view we were, but from a death-bowling point of view we were excellent,” Du Plessis said.
“It was really good that we could get tested against two set batsmen and the way we responded was great to see. Myself and Dave had to somehow get a score together, we talked about trying to get to 240 but with Dave’s power we were able to get going. We’ll remember this place fondly.”