Ireland's new-look side are determined to beat Argentina in their own back yard for the first time tomorrow and cement their places in Eddie O'Sullivan's World Cup plans.

The head coach has given his starting XV in Santa Fe plenty of incentive by revealing half the places in his squad are up for grabs.

With most of Ireland's Six Nations stars resting at home, the two Tests against the Pumas represent the perfect opportunity for their understudies to stake a claim.

One of the better known hopefuls is rugby league convert Brian Carney, who will make his international debut just two months after becoming a union player by signing a two-year contract with Munster.

O'Sullivan is looking forward to seeing his latest disciple in action.

"We have to know if he can make the transition to the next level up," he said.

"Probably, the one thing in his favour is that he's played at a pretty high level. And he has been in the cauldron of international rugby, albeit in league rather than union. But he seems to have the temperament.  I think Brian has adapted well."

Simon Best will captain the senior squad for the first time and insists he and his team-mates know where Argentina's strength lies.

"Argentina have been strong at scrummaging for a long time," he said.  "Every time you play Argentina, the scrum is one of the biggest plays they rely on. However, we have a good pack as well and will take this as an opportunity to us to showcase a big scrummage."

Ireland have enjoyed a keen rivalry with Argentina since the South Americans shocked them in a 1999 World Cup quarter-final play-off.  They gained revenge four years later in Australia, when Alan Quinlan scored the decisive try to help the Irish to a 16-15 victory.

Outhalf Paddy Wallace expects tomorrow's Test live up to that billing.

He said: "We've had great history with the Pumas over the last decade, we've had a lot of tough battles and we expect another one on Saturday.  It was great for the Pumas in 1999, it was great for Ireland in 2003 so it will be a good test for a young Irish side against more experienced Pumas side."

The sides meet again in World Cup combat in September, in the same group as hosts France, Namibia and Georgia.

O'Sullivan expects French scouts to pay close attention to tomorrow's game.   "If I were French, I'd send somebody to Argentina to watch the series," he said.

O'Sullivan has already said he would rather not play Argentina so close to the World Cup and Wallace, who will win his fourth cap, expects both sides to play a cagey game tactically.

He said: "Everybody wants to win the matches but with the World Cup only a few months away I think we will not show too many of our cards and I'm sure Argentina will be doing the same."

Nine of Ireland's starting XV at the Brigadier Estanislao Lopez stadium have fewer than 10 caps.

Some of Argentina's players will also be unfamiliar, with four of their starting line-up home-based players, with another four on the bench.