OGara takes charge in the absence of lock Paul O'Connell, who is struggling to overcome a disc problem in his back.

Clermont Auvergne and Llanelli Scarlets make up the group, and O'Gara - the Heineken Cup's record points scorer - admits the acute degree of difficulty leaves little room for manoeuvre.

He said: "We are in a very difficult pool, and it is one I would have preferred not to have been drawn in.

"It would have been nice to have avoided a couple of these teams at this early stage to allow us to catch our breath, but there is no chance of that.

"We have to be right from day one, and any slip-ups could mean we are under pressure.