The Irish launch their tournament against Eddie O'Sullivan's USA at Stadium Taranaki early on Sunday morning needing an emphatic victory to dispel memories of a troubled build-up.
A convincing start would also help banish any lingering shadow cast by Ireland's dismal World Cup four years ago when their campaign unravelled from the moment the group stage began.
Sexton, who starts at fly-half ahead of Ronan O'Gara, has revealed the more recent additions to the team such as himself, Conor Murray and Keith Earls are keen to set the tone.
"I was shocked at the way it went in 2007. The players were in such good condition, but it just didn't fall into place for them," he said.
"Hopefully the guys who were there have learnt from the lessons and will use their experience.
"But we have a lot of young lads who have no baggage and are dying to play in the World Cup.
"Hopefully that mix of youth and experience will be good. Maybe some of us younger guys can take the lead.
"The more experienced lads are humble, they don't mind being barked at by us."
Successive defeats to Scotland, France home and away and England were hardly ideal preparation for the World Cup, but morale has been good since the squad's arrival in New Zealand last week.
Sexton stressed the importance of not overstating the significance of last month, but accepted there can be no excuses if Ireland misfire over the coming weeks.
"There were some disappointing results. We wanted to win the games, I'm not going to lie about that," he said.
"Maybe at times we played those games like friendlies, viewing them just as warm-up games where results didn't matter.
"But this is the World Cup, this is what we're here for. Maybe we'll look back on those four matches as an important time when we learnt some harsh lessons.
"In 2007 the lads were undercooked and learnt a lot of lessons during the pool games.
"We wanted to make sure we had four really tough games to get a lot of the rustiness and mistakes out.
"Now we're set to go and there can be no more excuses from here on in.
"We're taking it week by week in the pool. All we want to do is get out of our group, we've learnt that from the Heineken Cup.
"When we do that we'll be three wins away from lifting the trophy and we can set our goals then.
"If we perform to the best of our ability we're capable of causing a few surprises."
Sexton will form an exciting new half-back partnership with Conor Murray, who was the surprise selection in Ireland's team.
Murray, at 22 the squad's youngest player, will be making his full Test debut as he continues a meteoric rise that only saw him break into the Munster team this year.
"Conor's had a great 2011. This time last season he was on a development contract and then got his break," said Sexton.
"Everyone's career starts at a certain point. He took his opportunity with Munster and impressed, then took his chance with Ireland and impressed there. He's gone from strength to strength.
"He's very laid back and I was shocked that he's so laid back.
"That's a good trait to have and he seems to take everything back in his stride. We seem to work together."
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