Samoa's 26-19 victory over Six Nations champions Wales at the Millennium Stadium on Friday lifts them one place to ninth and just 0.16 rating points away from a place in the second band of seeds for the next World Cup.
Cardiff has been a happy hunting ground for Samoa with two wins over Wales in Rugby World Cup matches, and the Welsh are now in danger of slipping out of band number 2 after falling two places to sixth on the back of a fifth successive Test defeat.
There was better news for Ireland, despite them not being able to influence the rankings as a result of playing a non-cap international with Fiji. Argentina and Ireland both climb one place to sixth and seventh respectively as a result of Wales' fall.
However, the sides ranked sixth to ninth are separated by just 1.1 rating points going into next weekend's matches when Ireland tackle Argentina in Dublin, Wales host New Zealand in Cardiff and Samoa clash with France.
On Monday, December 3, the IRB World Rankings will be used to determine the seeding of the 12 directly-qualified teams from the 2011 World Cup with the top four teams becoming band 1 and guaranteed to avoid each other until the knockout stages of England 2015.
The teams ranked five to eight will form band 2 and the remaining four teams band 3 with each band drawn randomly across the four pools for the 2015 World Cup.
If the draw was to take place today, the bands would be as follows:
Band 1: New Zealand, South Africa, Australia, France
Band 2: England, Argentina, Ireland, Wales
IRB WORLD RANKINGS (as of Monday, November 19):
Last week's positions in brackets -
1(1) NEW ZEALAND 92.91 rating points
2(2) SOUTH AFRICA 86.05
3(3) AUSTRALIA 85.94
4(4) FRANCE 84.99
5(5) ENGLAND 81.96
6(7) ARGENTINA 79.89
7(8) IRELAND 79.04
8(6) WALES 78.95
9(10) SAMOA 78.79
10(9) SCOTLAND 77.42
11(11) ITALY 76.61
12(12) TONGA 74.51