Ireland need to beat Argentina on Saturday to hold onto eighth position in the IRB World Rankings. The added importance of this will be borne out on December 1 when the 2011 Rugby World Cup pool allocation draw is made in London.
For the first time the IRB World Rankings are being used to seed the 12 nations who qualified automatically from the 2007 tournament in France.
The draw will see these teams split into three bands (Band 1 includes the world's top four-ranked teams, Band 2 includes the sides 5 to 8 in the rankings and Band 3 has the bottom four-ranked qualified teams in it).
As things stand, Ireland would be in Band 2 and thus have just one top-ranking team in their World Cup pool.
But should they lose to Argentina and Scotland beat Canada this weekend, Kidney's men would slip to ninth in the rankings and into Band 3 and therefore be pitted with two top-ranking sides in their RWC pool.
Commenting on the challenge of beating Argentina in order to stay in the top-eight, the Irish coach said: "It's going to be very physical. It's an unusual situation in that there's so much to play for - the ramifications for them to stay in the top four (of the rankings), the ramifications for us for not getting a result.
"They can get drop goals if you let them inside your half, they can pick off points like that. They do have a way of keeping the scoreboard ticking along. They have a strong set piece.
"You don't get to be ranked fourth by having a bad side. I was also interested looking at the South Africa match during the summer.
"After 30 minutes they were 9-0 up. Two months off with not a whole lot of pre-season under their belt but they showed what they can do.
"Every time you played them there was always something on the line over the last number of years .
"History is history...you have to see ten matches. It's five-all and they have won the last three. We just have to concentrate on our game."
Discussing the changes made to the side that lost 22-3 to New Zealand, Kidney agreed that once again there were a number of tight calls.
"Geordan (Murphy) has been playing well. Full-back is just an area that is highly competitive at the moment.
"It was tight over who would start over the last two weekends. We just thought he was the right man for this job.
"Stephen (Ferris) started against Canada. He played well. I would have had that in mind before last night's hearing (for Alan Quinlan).
"At hooker, it's a case of two guys playing well with a third man, Bernard (Jackman), breathing down their necks.
"Jerry (Flannery) played very well when he started against Canada and he played well last week. It's not that Rory has done a whole lot wrong. It is just a judgement call really.
"The provincial coaches know all about it - the six-day, seven-day or eight-day turnaround. That's the fine line and the way things go."
Best will take his place on the replacements bench, having recovered from a dead leg, while Paul O'Connell retains his second row spot after fighting off a similar injury.
However, Kidney has some other concerns as he looks to confirm who will take the back row vacancy left in the replacements.
"There are a number of concerns. Shane Jennings picked up a knee injury," he said.
"Denis Leamy, who had also been training with us, took a knock playing for Munster on Tuesday night. We'd be just hopeful that it would work out and Alan would be available."
The appeal of Quinlan's ban will take place in Dublin tomorrow (Friday) and the Irish management will await its result with interest.