Australia hit a massive 344-6 to set up their second successive VB Series victory over South Africa by 57 runs, reports BBC.
Adam Gilchrist hit devastating 88 off 66 balls in Sydney as Australia posted their second-highest score at home.
Also contributing were captain Ricky Ponting (72), Damien Martyn (79) and Mike Hussey, who hit 47 not out.
Mark Boucher blasted 76 in reply but the tourists were always behind and must now beat Sri Lanka Tuesday to reach the best-of-three finals.
Johan van der Wath, batting at eight, smashed 37 off 16 deliveries with four sixes, to make sure his side's losing score of 287-6 was the highest ever at the SCG.
South Africa, without key bowler Shaun Pollock, who is resting a bruised left heel, appeared powerless against Gilchrist after the hosts won the toss.
The wicket-keeper had brought up his half-century in the eighth over from only 29 balls in an impressive display of driving but was denied a 14th century in his 231st match.
Monde Zondeki saw his opening four overs dispatched for 42 runs before he was relieved of his duties by super-sub Charl Langeveldt, who made the breakthrough when Gilchrist miscued a pull.
The innings follows scores of 116 and 33 since he took a week off in an attempt to get out of a rut of poor form that had put his opening berth in doubt.
Skipper Ponting continued the onslaught in a 61-ball innings with eight fours, although he fell for the second time this series to spinner Johan Botha, lobbing a catch to midwicket.
Martyn helped him add 35 for the fourth wicket then played the senior role as he put on 60 with Michael Clarke (27), his 75-ball stay including just five boundaries. And Hussey hit a six off Van der Wath in a 33-ball cameo at the death.
Australia's only higher score at home came at the same ground two years ago, a total of 359-5 against India.
That equalled their highest ever total, hit against the same opponent in the 2003 World Cup final.
South Africa were behind the pace even before captain Graeme Smith gloved Brett Lee behind with seven on the board in the third over.
VB Series, Sydney: Australia 344-6 (50 overs) beat South Africa 287-6
(50 overs) by 57 runs
Only when Herschelle Gibbs and Boucher were putting on 53 for the third wicket did they look like catching up.
When Gibbs was smartly stumped off Andrew Symonds for 46, Boucher kept blazing.
The in-form wicket-keeper, promoted to fourth in the order, crashed two sixes before giving Nathan Bracken a catch in the deep in the 37th over.
All of the lower order contributed but by then it was with an eye to gaining form for Tuesday's vital meeting with Sri Lanka in Hobart.