World Rugby published the ranking permutations for the men's internationals in Europe and Africa this weekend, including the Autumn Nations Series, Rugby Africa, and Rugby Europe competitions.
South Africa cannot improve its rating and advantage at the top of the rankings due to the 18.77-point difference between themselves and opponents Wales before home weighting is factored in.
The fact that the same is true for Ireland in second place if they beat Fiji – with a rating of 10.71 points below Ireland – means the Irish cannot reclaim the top spot if South Africa also wins.
However, if South Africa loses to Wales then a victorious Ireland will return to the summit of the rankings, potentially by as little as 0.02 rating points.
New Zealand are the only team in the top three who can improve their rating in victory this weekend, but they would need the teams above them to slip up to stand any chance of climbing the rankings.
For New Zealand to become number one for the first time since the semi-finals of Rugby World Cup 2019, they must beat Italy in Turin and hope that South Africa loses by more than 15 points and Ireland is also beaten.
Fourth-place France needs a favour from Italy as well as beating Argentina in the opening match of the weekend if they are to climb above New Zealand into third.
Les Bleus can end the weekend in second if they win, New Zealand lose and Ireland are beaten by more than 15 points by Fiji – a scenario that would see France and Ireland swap places.
However, defeat for Les Bleus at the Stade de France will see Argentina leapfrog them in the rankings and move up to fourth.
Third place is possible for Los Pumas but they would have to win by more than 15 points and hope New Zealand suffer a similarly large defeat for that to happen.
Scotland cannot improve on sixth place this weekend despite being able to pick nearly a point for an emphatic win over in-form Australia.
However, if eighth-ranked Australia keep their Grand Slam tour hopes alive then they will replace Scotland in sixth place with the sides potentially swapping places.
Scotland could drop as many as four places to 10th if they are heavily beaten, Italy pull off a shock win against the All Blacks and Fiji avoid defeat in Dublin.
England cannot improve their rating against Japan this weekend due to the 9.36-point gap between the teams before home weighting is factored in.
They could even end a five-match losing run and still fall a place to eighth – equalling their lowest-ever position – if the match at Murrayfield ends in a draw.
A fourth defeat of the Autumn Nations Series could actually see England sink as low as 10th if they lose at home to Japan, Italy win and Fiji and Australia avoid defeat.
For Italy to equal their highest-ever position of eighth, they need to beat the All Blacks for the first time in history and hope that England and Fiji suffer defeats.
Fiji, meanwhile, could climb to an all-time high of sixth if they can beat Ireland by more than 15 points in Dublin and other results go their way.
Wales would need to be beaten by South Africa and England suffer defeat at the hands of Japan for them to drop to a new all-time low of 12th, with the Brave Blossoms replacing them in 11th.
Georgia, the side immediately below Wales, cannot overtake them this weekend as a win against lower-ranked Tonga won’t be rewarded with any rating improvement given the 8.40 rating points difference between the sides before home weighting is factored in.
With just two places between Spain and the USA and Romania and Uruguay, the result of those internationals could lead to significant change.
The USA can't improve on their present position of 15th this weekend, however, as Samoa have too big a points cushion for them to be caught.
Spain not only needs to overturn the result of last year’s La Vila International Rugby Cup final but also beat the USA by more than 15 points to overtake the Eagles in the rankings.
Romania, meanwhile, needs to beat Uruguay by more than 15 points in Bucharest to become the higher-ranked of the two nations.
Uruguay will climb above Spain if they win and Los Leones fail to beat the USA.
Tonga could move up the rankings by a couple of places depending on the margin of victory in Tbilisi and the outcome of other matches.