"In some ways any of those combinations were more fortunate rather than planned, to be fair," explained the Irish coach.

"It's a side that never played together before. What I'm trying to do is give them a basic template to play next week so they can all fit into some sort of a game-plan.

"Having said that, when you leave your starting 15 at home, it's always a challenge but that's the challenge in picking this team."

As the competition for World Cup squad places gathers pace, O'Sullivan added: "To be fair to the guys at home they did make their case in the Six Nations - a problem for all these guys they didn't get that opportunity. I'm trying to give them that opportunity now."

For photos of the Ireland squad in training at Centro Naval in Buenos Aires, click here (Part 1) and here (Part 2).