For a player who has shared three Six Nations titles with Ireland, two successful British & Irish Lions tours and seven championships with Leinster that is a big call.
Sexton, 34, told The Times, "Yeah, it's the biggest challenge and it is the most exciting. We said it after the Samoa game: 'Look lads, no matter who we play, this is the biggest game of our lives'.
"You feel it straight away. You feel it when you wake up this morning and your mind goes straight to the game. So sleep will probably be a challenge this week."
Sexton said he had childhood memories of the first time he saw Ireland playing at a World Cup was in 1995.
"It's where you want to be and it's where you want to challenge yourself. It's where we can create something a little bit special back in the country. I am sure the country will go made on Saturday morning, so I can't wait for it," he said.
Sexton will break another record in the game, being paired for the 56th time for Ireland with halfback Conor Murray. They will break a record held by Peter Stringer and Ronan O'Gara.
That will pit them against All Blacks Aaron Smith and Richie Mo'unga who have started only three Tests together.
"It's amazing we've got to this point if you saw us playing together at the start. I didn't think we'd last much further after three or four caps, to be honest.
"It's been a pleasure to play with Conor. He's world class on his day – world class all the time. I love playing with him. We've become great mates over the last few years and it's a little bit special to start that many Tests with the same guy. We've got a really good relationship now and hopefully it will be as good as it's ever been on Saturday," Sexton said.
He added that he had heard it said the only way you gained New Zealand's respect was by beating them.
"We've done that so hopefully they respect us a little bit. I don't know if they do. They'll have to answer that themselves. But all that stuff doesn't matter come Saturday.
"It's all about how we perform on the day under the pressure. That's going to be our big challenge over the next five days' preparing unbelievably well to do that," he said.