The Wallabies will be expecting to claim the full five points on offer against Russia, so Declan Kidney's men will need to beat Italy in order to seal a quarter-final berth as pool winners.
Forwards coach Gert Smal and scrum coach Greg Feek will be busy men in the coming days as up front has traditionally been where Italy's strengths lie.
Ireland needed a late drop goal from Ronan O'Gara to avoid a rare defeat to the Italians in last season's Six Nations, and Smal knows that the pack can ill-afford a drop in standards in this weekend's match.
The Irish scrum, which won some crucial penalties against Australia, will surely get a thorough examination from Martin Castrogiovanni and company.
"Italy pride themselves on their scrum. I think that aspect is going to be bigger than the Australian game (for us)," admitted Smal.
"Italy have a very heavy pack. They have a very good front row and a heavy back five. It's definitely one of the areas in which they will attack us.
"They also drive well from the lineouts and those are things that we have to counter. They've got sizeable backs so we will be tested in all areas."
Smal has plenty of respect for Italy captain Sergio Parisse, whom he rates as an 'outstanding, world class player', and their head coach Nick Mallett.
"I know Nick well. We played together and coached against each other in provincial rugby in South Africa."
The short five-day turnaround between Italy's 27-10 victory over the USA and this weekend's all-or-nothing encounter may prove a factor, but Smal says Ireland will not lapse in their preparations.
"We might be a little fresher, but we can't control when Italy play and what affects them. It's important we concentrate on what we can control and that we're ready for Sunday."
11 points is the most Ireland have conceded in their last four meetings with Italy. Mallett's men have scored two tries in their last three games against Ireland, one of those being a charge-down effort from Kaine Robertson in the 2010 Six Nations.
But as Kidney has pointed out, Sunday's showdown is effectively 'a cup final' given the prize at stake. Anything can happen in such a 'one off' game, and defence coach Les Kiss will want a watertight display in the tackle area and elsewhere.
"We were in the position to have the best defence after round three. That isn't the case now, but it's still a good effort by the boys," said Kiss, after Ireland leaked tries to Russia's Vasily Artemiev and Denis Simplikevich.
"The USA try was an intercept and then there were the two against Russia. There are things to work on and this will make us hungry to improve, which is important.
"We're concerned when a point goes against us, particularly at set piece. We are usually very good at defending set pieces."
Follow the Ireland team in New Zealand on www.twitter.com/irfurugby.