France will take a step closer to a first RBS Six Nations Grand Slam since 2004 with victory over Italy at the Stade de France on Sunday, but they cannot improve their position of the fourth in the IRB World Rankings.
This is because even an emphatic victory over a side ranked 11th and 12 rating points below them will not have any impact on their total of 85.22 rating points, leaving them just over three tenths shy of Australia in third.
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Les Bleus cannot lose fourth place as long as they continue their perfect record against Italy in the Six Nations, because even if Ireland beat Wales by more than 15 points at Croke Park the day before they will still trail France by six tenths.
However, if Italy were to build on their defeat of Scotland a fortnight ago - the Azzurri's first Six Nations victory for two years - and end France's hopes of a clean sweep than their hosts will swap places with a victorious Ireland.
An Italian victory at the Stade de France - allied with a Scottish loss to England - would see the two sides swap places, while Nick Mallett's side could actually climb to ninth - their highest position for more than two years - with an emphatic win.
Ireland will be looking to mark captain Brian O'Driscoll's 100th test for his country with a victory, although even a win on home soil by more than 15 points can only improve their rating by two tenths.
In hot pursuit
The good news for Ireland, though, is they cannot relinquish fifth spot, even if Wales were to win by more than 15 points. However, if this happens, and England also beat Scotland by a similar margin, then only six hundredths would separate the three rivals.
If Ireland do suffer a second heavy defeat of the 2010 Championship - following a 33-10 loss in France last month - then the defending champions will trail France by 3.55 rating points and lie more than 10 point adrift of number one side New Zealand.
A repeat of Wales' victory on their last visit to Dublin will lift them above Argentina into seventh place, regardless of the winning margin. Warren Gatland's side could actually climb another place to sixth if they win and England suffer a third successive Calcutta Cup defeat on Scottish soil.
This outcome, regardless of the final results, would effectively see Wales and England swap places with Argentina's only chance of improving their position of seventh dependent on both teams suffering away defeats.
Auld Enemy
Scotland will be eager to bounce back from that defeat in Italy and have the added motivation of wrestling the Calcutta Cup back from the Auld Enemy. However, simply retaining the Cup, will not be enough to improve their position of 10th.
In order for that to happen, Scotland must beat England in the world's oldest fixture on the rugby calendar by more than 15 points at Murrayfield, something they have not managed to do since the Championship became the Six Nations.
If they can break this sequence, then Scotland will reclaim ninth place from Fiji.
The RBS Six Nations is not the only competition which could impact the IRB World Rankings this weekend as the European Nations Cup continues with Portugal and Romania seeking vital wins as they attempt to keep alive hopes of joining Georgia and Russia at Rugby World Cup 2011.
Look out a preview of this weekend's European Nations Cup matches and the permutations for the IRB World Rankings on Friday.
Scotland v England match preview statsIreland v Wales match preview statsFrance v Italy match preview stats
The IRB World Rankings update every Monday at 12:00 UK time.
