South Africa completed the Test and one-day double over Australia with an eight-wicket win at the Adelaide Oval.
Hashim Amla and AB de Villiers shared an unbroken 144-run stand to see the Proteas to a victory target of 223 with 11.5 overs to spare in the fourth one-day international.
The result gives the tourists an unassailable 3-1 lead in the one-day series ahead of the final match at the WACA on Friday and puts the seal on a magnificent tour.
South Africa also won the Test series 2-1, their maiden victory in the five-day format on Australian soil.
Chasing a modest target, Herschelle Gibbs gave South Africa's run chase a flying start by thrashing eight boundaries in a contribution of 38 from 29 balls.
Gibbs was caught via the top edge off Ben Hilfenhaus (1-49) in the 10th over and Jacques Kallis (13) soon followed, smashing medium pacer James Hopes (1-28) straight to midwicket, as the Proteas were pegged back at 79-2.
But Amla and De Villiers ensured there was no collapse with a partnership that was initially measured but finished with a barrage of strokes against their increasingly forlorn opponents, whose Australia Day celebrations were well and truly ruined.
Amla's contribution was 80 off 103 balls, while De Villiers - who also kept wicket due to Mark Boucher's broken toe - took a more aggressive approach to finish with 82 off 85, including six fours and a six.
Earlier, Australia had struggled to a below-par total of 222 all out in 48 overs after opting to bat first.
Ricky Ponting's 63 was the main highlight of a patchy effort from the hosts, who subsided from a position of strength at 110-2.
Opening pair David Warner (1) and Shaun Marsh (13) both departed inside the first three overs as Australia found themselves in early trouble at 17-2.
Ponting and Mike Hussey repaired the damage with a 93-run, third-wicket stand in just 99 balls.
But both were dismissed in quick succession - Hussey (28) trapped lbw by off-spinner Johan Botha and Ponting caught at cover off Makhaya Ntini in the next over.
And when Botha (2-28) struck again to remove Brad Haddin (3) - who failed to clear the midwicket boundary with a wild heave - Australia found themselves 130-5 at the mid-point of the innings.
Hopes posted a responsible and well-paced 42 off 44 deliveries, sharing a 37-run stand with Cameron White, who made a fighting 30 before getting out chasing a wide Dale Steyn delivery.
Wickets fell at regular intervals, Steyn finishing with 3-49. Ntini took some early punishment from Ponting but fought back to end with figures of 3-52.