Johnny Sexton says Ireland are preparing for the "toughest game we've ever faced" in Saturday's World Cup quarter-final against New Zealand.

"I've had some great battles against New Zealand over the years," he said.

"What you learn is that every game is as tough as the last no matter what the result is."

Fifteen months ago, Ireland fought back from a 42-19 First Test hammering in Auckland to clinch an historic series triumph in New Zealand and the Irish have won four of the last six meetings between the countries.

However, Sexton says the Irish will be facing a "different" All Blacks in Paris as they attempt to get past the World Cup quarter-finals for the first time.

"That's what we're preparing for. We're preparing for the toughest game we've ever faced and we're trying to put ourselves in a frame of mind that we're going to be ready for it," added the 38-year-old who will retire from rugby after playing at his fourth World Cup.

Joe Schmidt, who coached Ireland to three Six Nations titles and the 2018 Grand Slam, is part of the management team of New Zealand coach Ian Foster and Sexton says his imprint is obvious in an All Blacks team which won this year's Rugby Championship.

"You can see evidence of Joe's coaching through the team. They've made big strides over the last 12 months and I know they have a different forwards coach [Jason Ryan] as well from when we were there.

"We know that it's very much a different team that we're playing against. They've said it themselves. It's a big challenge."

But while Sexton has the height of respect for his former Leinster and Ireland coach, who he says left a "massive" legacy on Irish rugby, he added: "Joe doesn't get to make any tackles or run any lines at the weekend.

"We just have to worry about the players we are playing against and not too much about him."

Asked whether Saturday's contest is a mental as well as physical battle for the Irish having never won a World Cup knockout game, Sexton replied: "We've worked on our mental game for the past four years and put ourselves in different scenarios to prepare for this.

"Each quarter-final that we've haven't got through, or we haven't got through our pool, they've all been different and it's a different group [of players] again.

"Each of those groups lost once. It wasn't the same group losing quarter-finals year after year.

"If it was club rugby it would probably be a bigger hurdle. I don't think we've carrying much baggage. It's a one off game we're preparing for now."

'We didn't dream of winning a World Cup'

Despite admitting that the notion of winning a World Cup would have seemed unthinkable during his childhood, Sexton insisted that he is not burdened by the weight of expectation as Ireland approach what many feel could prove an opportunity that doesn't come round again.

"Trying to win a World Cup... it's something to go and get. It's not something that puts pressure on me.

"It's something that you dream of probably not as a kid because when we were kids, we didn't dream of Ireland winning a World Cup.

"We've put ourselves in a position now to go and do that but it's something to go and get. It's not something to be pressured about."

And when it was put to him that Saturday could be final ever game, Sexton replied: "I haven't thought about my own career to be honest. I'll think about it more when I finish.

"It's all about the team and progressing in the competition. That's all we're thinking about. It's not about anything personal."