Rory Best has conceded Ireland's confidence has been dented by the shock loss to Japan – but insisted Joe Schmidt's men are still "very assured" of how to hit back to World Cup success.

Ireland ground to a patchy 35-0 bonus-point win over lowly Russia on Thursday, leaving victory over Samoa standing between Joe Schmidt's team and the World Cup quarter-finals.

Ireland will face on Samoa on Saturday, October 12, with the squad intent on taking full advantage of a rare fallow weekend to rest and recuperate – then sharpen up.

"I think when you lose a game and go from being supposedly contenders in the first game to useless in the second game it's always going to affect he confidence a little bit," said Best.

"But we bounce back well, and this group understands what we need to do to play well.

"We understand our core values, and we know we weren't as good in those areas against Japan.

"But you look back at the warm-up game in England and then the two games against Wales and then Scotland here; we felt we were improving.

"Sometimes you've got to take it on the chin and say we didn't play as well as we can, Japan played very well and put us under pressure.

"But in terms of confidence in the group we're still very assured of what we're capable of and how we get there.

"Our destiny is still in own hands. So we're there and thereabouts, but we would have expected to be in a better place after the three games.

"We would have expected to win the three games but that hasn't happened.

"We know a bonus-point win will guarantee our place in the quarter-finals.

"We were always here to make the quarter-finals, we've made no secret of that and that's what it comes down to now.

"We started the Japan game really well, 12-3 it's not a place where we expect to lose a game from.

"Traditionally when we get ahead we're a hard team to stop. But we made a few uncharacteristic mistakes, so there's a lot we need to work on.

"We have time to reflect a little now and it's very, very rare to have a weekend with no game, so it's really important we utilise that."

Johnny Sexton captained Ireland for the first time in the five-try win over Russia, the British and Irish Lions fly-half withdrawn at half-time as a precaution.

World Cup skipper Best hailed Sexton's leadership qualities, insisting that element of the 34-year-old's game is sometimes underestimated.

"I think Johnny is a fantastic captain; the problem when you get somebody as good as Johnny the tendency sometimes is to focus on some of the negatives," said Best, of Sexton.

"But if you look at the way he's led Leinster, not a lot's been said about how successful they were last year.

"A lot's been said about that game in Thomond Park and focused on that. But whenever you see the way Leinster play, you see that they want to play for him.

"And I think the sign of a really good captain is that you get a sense that people want to play under you.

"I think you got that from Leinster last season, and you got that from the boys last night.

"He's definitely maturing into somebody who understands the difference between being a quality player and being a quality captain.

"And I thought he did really well, I thought he had a really strong 40 minutes, not just as a player but also as a captain last night.

"And there's no hiding away from the fact that he's a big, big leader in this group."