Australia's victory over Argentina combined with New Zealand's victory over South Africa has moved the Wallabies above the Springboks who have dropped to third place.
Australia beat Argentina's Pumas 19-25 largely thanks to the boot of Mike Harris as he kicked 20 points at the Estadio Gigante de Arroyito in Rosario on Saturday to also give the Wallabies second place, albeit a distant one behind champions New Zealand, in the inaugural Rugby Championship standings.
Only four tenths had separated South Africa and Australia going into the final round of matches, but the Springboks' 32-16 loss to New Zealand in Soweto had put their second spot on the line.
The difference between the two sides has now grown to 1.23 rating points, although both Australia and South Africa have seen their rating go down over The Rugby Championship.
New Zealand's four-try victory - their 16th Test consecutive win - at FNB Stadium increased their rating by just over nine tenths to now sit 7.43 points clear at the top of the IRB World Rankings.
The All Blacks have occupied top spot since 16 November 2009 and their clean sweep in The Rugby Championship has seen that cushion increase by 3.05 points.
Argentina remain eighth after their first taste of The Rugby Championship, but are now less than a point above Scotland, placing their position in the second band of seeds for the Rugby World Cup 2015 Pool Allocation Draw on 3 December at stake.
IRB World Rankings -
08 October 2012 Position (last week)
1(1) NEW ZEALAND 93.35
2(3) AUSTRALIA 85.92
3(2) SOUTH AFRICA 84.69
4(4) ENGLAND 83.09
5(5) FRANCE 83.03
6(6) WALES 82.26
7(7) IRELAND 79.85
8(8) ARGENTINA 78.63
9(9) SCOTLAND 77.97
10(10) SAMOA 76.23
11(11) ITALY 76.03