Martin Gaitan (right) celebrates. (Getty Images)

By Simon Stone, PA Sport, Sydney

Argentina coach Marcelo Loffreda is banking on his team to produce their best performance of the World Cup against Ireland in Adelaide on Sunday.

The Pumas set up the make-or-break quarter-final qualification clash with a convincing 50-3 victory over Romania at Aussie Stadium, which leaves them level on points with Eddie O'Sullivan's men and one win away from a place in the last eight.

Loffreda admitted his side flopped badly the last time the spotlight was on his team during the opening-day encounter with Australia.

However, big wins over Namibia and the Romanians have convinced Loffreda his team are on an upward curve.

"I am confident we will produce our best performance of the tournament on Sunday," he said.

"What we achieved here has given us something to work on. I am fortunate to have 30 players in my squad who play at roughly the same level, which means I have been able to swap them around a little bit.

"I am close to selecting my side to play Ireland but I do know those who play will be fully rested for such a big game."

Yet again Loffreda expressed his discontent with a fixture list which forced the Pumas to complete their four-match programme in 16 days, while Ireland have been given an extra five to get through theirs.

"It is strange this has happened given we got to the quarter-finals last time and Ireland didn't. But we are here now and we have to get on with it.

"Ireland are a top side but we will put everything we have left into it and hope things go our way."

Romania coach Bernard Charryere has tipped Ireland to come out on top at the Adelaide Oval, even though his team suffered a heavier defeat now than they did against the Irish.

Number eight Pablo Bouza and full-back Juan Hernandez both scored twice in the seven-try romp but it was not enough to convince Charryere the Pumas have what it takes to repeat their shock play-off win against the Irish four years ago.

"Argentina have some very good players, who will give anybody a hard time," he said.

"But they are not capable of reaching the same level as Ireland, and that's why I believe Ireland will win."

Romania at least had the satisfaction of bringing the loudest cheer from an enthusiastic 33,000 crowd when Ionut Tofan stroked over his team's single penalty.

After being hammered by Ireland, Australia and Argentina, Romania now move on to their final group match against fellow minnows Namibia next Thursday knowing victory is required to launch the next stage of their fight for recognition within the game.

"We thought we had turned a corner with our performance against Ireland," said team manager Florin Campeanu.

"The subsequent matches have shown us just how far we have to go. Over the next 12 months we will strive to get back into the second division of world rugby."