Ireland coach Joe Schmidt said that Saturday's game against Argentina will probably wind up as the most difficult game of the November series.
Ireland's November programme concludes against the Argentinians this weekend, following wins over South Africa and Fiji in the past fortnight.
A full strength Ireland demolished South Africa 38-3 in the opening game of the series, before a largely second string outfit laboured to a 23-20 win over Fiji last Saturday.
Speaking to RTÉ Sport, the Ireland coach says that the Argentina will probably end up being the trickiest game of the month.
"It ends up being the toughest game now. Argentina have improved. It's really difficult to gauge improvement by results.
"They play the top teams in the world all the time. They are incredibly competitive against those top teams.
"Speaking to the South African coaching staff, they said it was very, very tough against Argentina in both games. Now, they (South Africa) got away and they won them. But they said there were periods in the games when it was really in the balance.
"Argentina - if they feel they are in a position to win the game - are going to be incredibly competitive. It's going to be our responsibility to make sure that doesn't come about because we're going to have to keep the pressure on them."
Schmidt said he was delighted that Marty Moore is to return to Ireland after two seasons playing in the English Premiership with Wasps.
Moore rejoins Ulster in the summer.
"We're delighted that Marty has gone forward to Ulster. He hasn't gone back. Because, in my discussions with Marty, that's what he wants to do. He wants to go forward.
"I think it's a great opportunity for him to get some quality game time. He's only had two starts this year, accumulated maybe about 200 minutes.
"He'll want to roll his sleeves up and start to get into a game rhythm that'll make him competitive and promote his opportunities further up."
Live coverage of Ireland v Argentina begins on Saturday on RTÉ 2 television and RTÉ Player at 4.30. Live commentary is on RTÉ Radio 1’s Saturday Sport, which starts at 2.45, and you can follow all of the build-up and action on our live blog online at rte.ie/sport and on the News Now app.