More often than not, the All Blacks were the best team in the world, he told media this week, and Ireland would face a challenge at the weekend.
"I think it's the intensity that they bring to the game, the physicality. By intensity, I mean the speed they play at, and at the same time being physical," he said.
"We know what's coming because we've played against them so many times, but there's a few lads who haven't played against them that we have to let them know what it's like out there against them," he said.
"All the focus is on making sure we can get our best performance out there at the weekend. We know what quality they possess, we know their coaches quite well, having been coached by Greg Feek and John Plumtree before.
"We know the strengths that they bring so, we've got to make sure we're in the best place possible come Saturday," he said.
The game could have a personal challenge for Sexton, another appearance against Beauden Barrett should he be named in the All Blacks side.
Both have achieved their 100th cap in recent games and have a rivalry extending back to 2012.
"He's an outstanding player," Sexton said.
"Whether he plays at 10 [first five-eighths] or 15 [fullback], he brings his strengths to the game. He's just a freak of a runner, and he has a lot of skills with it: a great kicking game and those kick passes that he can do, chipping it to himself or for others. He is a strong guy.
"He can go to the line well and he can pick a pass. He has it all really. He's one we'll have to look out for. Whether they go for him at 10 or what, I'm not sure at this stage. Whoever gets that, Beauden will be in the team somewhere so he is obviously a threat, one of their biggest threats," he said.
While Ireland had twice lowered the All Blacks' colours in Chicago in 2016 and in Dublin two years later, Sexton said they hadn't been able to beat them in the biggest game of all, the 2019 World Cup quarterfinal.
"We didn't play as well as we could have. We made mistakes which they capitalised on, we didn't take the chances we had, and that's the game.
"If they go a couple of scores up, they are very hard to chase down. We've got to concentrate on ourselves and make sure we can get the very best performance we can out on the pitch and see where that leaves us, That's where all our focus is on at the moment," he said.