Ireland’s final Pool A encounter against Samoa marks the start of the “business end” of their tournament, says defence coach Andy Farrell.

A win in Fukuoka on Saturday guarantees Ireland a place in the last eight, but they can only top the group if Japan are defeated by Scotland without collecting two bonus points.

“[It is] probably a week early but it is the business end,” said Farrell.

“The different permutations are not something the boys are thinking about.”

He added: “The only thing that matters for us is our preparation, which has started pretty well.”

Ireland’s tournament to date has done little to ease concerns over their consistency, with an impressive performance against Scotland being followed by a loss against Japan and an underwhelming victory over Russia.

Despite the contrasting displays, the messages being sent out from the Irish camp have remained the same throughout the course of the campaign, emphasising the solidarity and mood of optimism within the group.

Andy Farrell hopes Ireland will have a clean bill of health for Saturday's game against Samoa with Johnny Sexton (right) expected to start

“There is a positivity within our camp that we are able to be honest with each other,” Farrell said.

“Honest feedback can be portrayed as super-positive in one way or it can be portrayed by others as a little bit negative.

“We don’t feel like that because we are able to speak to each other how we want.”

Farrell, who will take over from Joe Schmidt as head coach at the end of the tournament, dismissed ideas that Ireland may seek to rest some players in preparation for a potential quarter-final against New Zealand or South Africa.

“It’s definitely not an option,” he said.

“This game is super-important to us and we are fully in, we are after the best performance of the competition.”

With Robbie Henshaw and Joey Carbery available for selection and Jordi Murphy’s speedy recovery from a rib injury, Ireland appear to have a clean bill of health.