"In some ways any of those combinations were more fortunate rather than planned, to be fair," explained the Irish coach.
"Itâ00s a side that never played together before. What Iâ00m 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, itâ00s always a challenge but thatâ00s 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 â00 a problem for all these guys they didnâ00t get that opportunity. Iâ00m trying to give them that opportunity now."