A shock defeat for the All Blacks to the Wallabies in Perth on Saturday night will be a double blow for the World Cup winners.
If Steve Hansen's men fall to Australia in the opening Bledisloe Cup test it will mean that they will give up the top ranking in World Rugby to Wales, along with most likely the Rugby Championship.
Following the 16-16 draw to South Africa in Wellington, the All Blacks now hold a 1.58 point lead in the rankings over Wales. A loss in Perth would see the All Blacks drop by 1.66 points and into second spot, according to Wales Online.
However it could only be shortlived in Wales don't beat England at Twickenham on Monday morning NZT in the first of two tests dubbed as 'warm-ups' ahead of the World Cup.
Last month Hansen said the rankings mean nothing ahead of a World Cup.