Eddie O'Sullivan believes the selection of Beauden Barrett at full-back rather than out-half is a positive for Ireland ahead of Saturday's World Cup quarter-final meeting in Tokyo Stadium. 

Barrett, the World Player of the Year in 2016 and 2017, has been named at full-back with Crusaders out-half Richie Mo'unga operating at 10. 

Ireland have won two of their past three encounters with New Zealand but enter the game as clear underdogs, a consequence of their extremely patchy form in 2019 and their relatively undistinguished history in the competition itself. 

However, the former Ireland coach thinks Joe Schmidt's team has a far more settled look heading into the weekend. 

"That's a strong New Zealand backline but it's not the perfect backline," O'Sullivan told the RTÉ Rugby Podcast. 

"I'm really happy about Barrett being at 15 because I don't think he's going to get his hands on the ball as much.

"He's a massive catalyst for New Zealand in attack. He's a very smart defender as well. He can really cause problems when he's on the ball. I don't think he gets his hands on the ball as much when he's at 15. It's practically impossible to bring him into the game as much as Richie Mo'unga will be.

"I think those selections give us a little chink of light in terms of exploitation. I'm sure they're looking at us the same way. But we're much more settled than they are.

"If you look at the selection that Joe Schmidt has put out, that's basically his best hand on the table, the most experienced team he can play.

"Joe's got a very predictable, very solid, very experienced XV, compared to the All Blacks XV which is not as experienced and I would say not quite as solid."

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While O'Sullivan argues Irish success hinges on defensive solidity against a New Zealand who rarely fritter away opportunities, he pinpoints certain vulnerabilities in the All Black make-up this time around, particularly in terms of goal-kicking and their discipline at the breakdown. 

"I think they'll look closely at the defence we used the last time we played them in Lansdowne Road. We kept them pretty much scoreless. They got two penalties and a drop goal. They didn't cross the whitewash which was massive. Our defence is going to be huge. That's down to a lot of energy and teamwork.

"We probably play our wings high and take away the space in the corners. I think you can do that against Richie Mo'unga, I'm not sure you can get away with it against Beauden Barrett as much. 

"Richie Mo'unga has not a great kicking game. He's not as astute at exploiting (the space) in the backfield. That's good for us. Especially, if it's wet. 

"It's another weakness. It's hard to believe we're talking about All Black weaknesses. But they don't have a really front-line, high percentage place kicker. Mo'unga seems to be the one they go to more often when both of them are on the field. He seems a bit more reliable. But neither of them are lock steady.

"When you compare them to Sexton, if it comes down to a drop goal or a late penalty in a one-score game, that gives us an edge there. If you comes to that, I'd back us to win that sort of a battle in terms of the goal-kickers shooting it out.

Richie Mo'unga in action against South Africa

"The other thing about New Zealand is that they have had trouble with referees around offside and coming in from the side at rucks. I'm not talking about discipline in terms of foul play, I'm talking about giving away penalties at breakdowns and stepping offside at rucks. 

"They've had a bad record of giving away kicks at goal. They do give up points, they've averaged 19 points conceded this year but because they usually score 25, 30, 40, nobody pays much attention to it.  

"I think this New Zealand team, overall, is not as strong as the New Zealand team that won the World Cup four years ago. That was a better team. I'm not saying they won't win the World Cup because even a bad New Zealand team is a very good rugby team. And this isn't a bad New Zealand team by any stretch. I'm just looking for chinks of light where we might have the edge on them."

Steve Hansen's team arrive into this game having not played in two weeks, the final pool game against Italy having been cancelled due to Typhoon Hagibis. 

Their only significant game thus far was against South Africa on the opening weekend. New Zealand were under the cosh for much of the game but rustled up 14 points in a blistering three minute spell in the first half which proved decisive in the end. 

"South Africa caused them lots of problems for most that game in terms of the way they defended and they (New Zealand) got two tries and a penalty in the space of six or seven minutes and that was the game right there.

"They don't have to dominate the game for 80 minutes to beat you, they just have to find the sweet spot and stick together 15 or 20 points and the game is over.

"For that reason, they're still an extremely dangerous outfit. Even if we believe that there are slight weaknesses here and there. 

"I still fancy our chances looking at the two line-ups and the longer the game goes on and it's tight, the better it is for us. I don't think we're going to put a score on them. But we know they do have that capacity. If you make mistakes, they will capitalise. They don't tend to waste opportunities." 

George Bridge scoring New Zealand's opening try against South Africa

New Zealand have not lost a World Cup game since Graham Henry's dominant outfit were shocked by France in controversial circumstances in the 2007 quarter-final in Cardiff. 

As usual, a nationwide inquest followed and O'Sullivan says this is one factor which separates this encounter from last year's game in Lansdowne Road. 

New Zealand's need to win - or their need to avoid the ignominy of losing - is much greater this time.  

"This is not like playing the All Blacks in an autumn international. It's a different level. If you think about it from New Zealand's point of view, if these guys have to get on a plane and go home next weekend, their life won't be worth living when they get back to New Zealand.

"It'll be misery upon misery for a long time. To go out of the World Cup in the quarter-final, there was pretty much chaos about it in 2007. 

"These guys are going to be playing for their lives. So, it's a different New Zealand than came into Dublin in November at the back end of their season. We were the better team in Dublin, we deserved to win that game. It was all chips on the table but it wasn't a World Cup knockout.

"It's probably a different New Zealand team that shows up in the sense that they'll bring more intensity than they brought in Dublin and we have to match from the start. But I still think we have to play some good rugby to get past them."  

Follow Ireland v New Zealand on Saturday 19 October (kick-off 11.15am) via the live blog on RTÉ.ie/Sport and the News Now App, watch live on RTÉ2 or listen to live match commentary on RTÉ Radio 1. 

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Follow all four Rugby World Cup quarter-finals this weekend via our live blogs on RTE.ie/Sport and the News Now app, or watch live on RTÉ2.