"That's the reality of playing the best team in the world."
Head coaches Steve Hansen and Joe Schmidt sparred on Thursday over which side could claim the tag of underdog at the Aviva Stadium, with the bookies favouring New Zealand to win.
But Best said the label was no more than media chatter, and the furthest thing from his troops' minds as Saturday approached.
"There will not be any talk in the changing room before we go out there about who the favourite and underdog is, it'll be about knowing we have to perform," Best said.
Despite the surprise victory two weeks ago, Ireland were highly critical of their defensive effort on US soil, conceding four tries and almost falling victim to an All Blacks comeback.
Best said there were plenty of instances in Chicago in which his side erred from their defensive system, and would need to rectify that this time around.
Both sides head into the match on the back of large wins over Canada and Italy respectively.
"If a team does unbelievably well and pulls a rabbit out of the hat and scores a try but our system is good, (coaches are) reasonably happy," Best said.
"But for us, when we look back at some of those scores and some of the breaks we let New Zealand get away with, there are a lot of improvements we can make."
- AAP