Ireland's greater confidence since recording its first wins over the All Blacks - in Chicago in 2016 and at home in Dublin in 2018 - would ensure its determination to claim another New Zealand scalp.
Coles expected Ireland to produce another tight tussle in the way it had in the last five or six outings.
"They're a different beast at home. They'll be feeding off the crowd in a full stadium, so it's a great challenge for us," he said.
The final two Tests of the year were going to be massive for the side, and the coaches and leaders had big tasks ahead of them to ensure the side was well prepared.
Coles said Ireland's defence was their strong point in their recent outings.
"They keep turning up. It seems like there was no space for us to attack.
"Their defence is awesome. They put some big shots on and put us under pressure and played a bit too much footy, so I suppose the kicking game might come into it a bit," he said.
"We're under no illusions. If we don't perform this week…the boys have worked so hard to turn things around from last year. It's still one week at a time, but there's two massive games [against] two quality oppositions [Ireland and France]. We'll get Ireland first, and see how we go."
Joining the tour late, Coles said he found there was still plenty of energy and enthusiasm among the players involved from the outset. Part of that was due to not having played too much rugby.
"I've been checking in with a lot of the lads, and they reckon it's gone pretty quick. The boys are still keen to be in the environment.
"The whole group has an important part to play this week regardless of if they're playing or not. It's a massive Test match, and we know the guys who are not playing have a responsibility to prepare the boys who are playing.
"It'll be a collective effort this week," he said.
Coles said the weekend's experience in Rome showed the difference between playing a team like the US Eagles and Italy.
As a Six Nations member Italy was exposed to many more top teams than the US and knew how to cope with the greater demands. That lesson was imprinted for the less experienced players as a result of Sunday's game.
"Every game is different, and I reckon they'll take a huge amount out of it," he said.
There hadn't been any panic on the field. It had taken a little longer than usual for corrections to be absorbed. He added it had been a collective disruption and was not confined to the inexperienced players.