If their results in the GUINNESS Series games against South Africa and eighth-ranked Argentina cause them to fall to ninth, they would enter the third tier and get a tougher pool draw in the process.
Mike Ross is well aware of how much is riding on Saturday's result against the Springboks, with the men in green also keen to improve their record at the Aviva Stadium.
"You certainly don't want to end up in a pool with two other heavyweights. It makes it that much tougher to qualify for a World Cup quarter-final," said the tighthead prop.
"It is very important that we do well in this Series, especially against Argentina who are just a couple of ranking points ahead of us. We don't want to slip down, we want to do well.
"We have a home record at the Aviva to look at as well. It hasn't been where it's needed to be in the last couple of seasons. It's a big challenge for us to step up to improve that."
Ireland's home run is heading in the right direction - they beat Italy and Scotland in their last two outings in Dublin during the 2012 RBS 6 Nations.
They will also draw confidence from their 15-10 defeat of the 'Boks at Croke Park in November 2009, a tight encounter swung by Jonathan Sexton's haul of five penalties.
Sexton and company come into the new campaign determined to banish memories of their 60-0 loss to New Zealand from four-and-a-half months ago.
Anthony Foley, who is overseeing Ireland's defensive plans during the November internationals, admitted: "The guys who played in that Test match (in Hamilton) will have that ringing in the back of their heads every night they go to bed - because it's a horrible place to be.
"It's not the first time it's happened. I've been involved in a few nightmares (as a player) as well.
"What you look for the next time out is making sure you can right that wrong. And it's a massive opportunity for that 23 who go out to put that to bed and not so much forget about it, but make it a driving force for you through the game and through the campaign."
The Ireland team and replacements for the clash with South Africa will be named on Thursday afternoon.
The recently arrived Michael Bent could well be named on the bench despite having not yet played for Leinster since he touched down on Irish soil last week.
Asked about the newcomer who will challenge for his number 3 shirt at Leinster and Ireland, Ross said: "If he is doing well against the top two or three looseheads in Ireland, you have to think he will be well able for the international stage.
"There are other Irish players who have played for Ireland without playing for an Irish province. You look at Kevin Maggs who was playing for Bristol and Geordan Murphy spent most of his time at Leicester.
"The fact is he is probably one of the guys out there who is match fit at the moment and has a good season at Taranaki.
"I think he has every right to be here and if he plays well nobody will be saying a word about him."