O'Brien: We have to leave ourselves in best position

"It is what it is. We are in the position we are in now. We have to live with that and leave ourselves in the best position after this weekend," he said.

The Tullow man is guaranteed to return from a three-day illness that took him out of the Leinster side to play The Scarlets last Saturday.

"I wasn't feeling great, didn't have too much energy come the weekend," he said. "It was better to sit it out, probably, than exhaust myself."

He knew then what everyone knows now. It has all come down to the last round. Munster are ranked ninth at present; Leinster 10th.

This in itself does not breed confidence. But, there is more than a glass half-full message in the details and permutations. Both can still make it if they secure bonus-point wins. It will most likely be one.

Certainly, Munster must be in the driving seat. They have a disinterested Racing Metro at home at Thomond Park. Leinster have the always interested Exeter Chiefs at Sandy Park.

The naked statistics do not look appealing for Leinster. Exeter have played 10 competitive matches at Sandy Park this season, winning seven, drawing one and losing to Northampton Saints and Clermont-Auvergne, the latter taking a winning bonus points for the first time since 'God knows when'.

In fact, The Chiefs have not conceded a winning bonus-point in the Aviva Premiership since they climbed to 'The Promised Land' in the Autumn of 2010.

In their three seasons, they have played 29 home matches, winning 18, drawing one and losing 10, never coughing up four tries in the process. This is a measure of the mountain facing Leinster.

The champions did all the research, the checks and balances, ahead of round one with Exeter: "Going into that game, we didn't think they were like that.

"Their work-rate is outstanding. It is something they pride themselves on. They are a very fit team. They have a very strong set-piece, are very dangerous. They caused us a lot of upset the last day at the ruck --counter-rucking and causing a nuisance really.

"Hopefully, it won't be as big a problem. We know all that about them now and how they can play as well when they have the ball."

If you want a brick wall broken down, O'Brien is your only man to take you over the gain line and in behind the first line of defence where Leinster's instinct can be a killer.

"They are very organised. We need to get over the gain line and set the tone from there. It will be a big week for anyone carrying the ball."

None will carry it harder than O'Brien.