Andy Farrell insists New Zealand will still be "top of the tree" even if Ireland beat the All Blacks in their Test showdown this week.
New Zealand will retain the world No.1 ranking even if world No.2 Ireland win in Dublin on Saturday.
The All Blacks' top-dog status would have been under threat had they lost to England last weekend but their 16-15 victory means the back-to-back world champions will end the year on top.
New Zealand boss Steve Hansen has already this week insisted Saturday's victor should be viewed as the world's best but Ireland assistant coach Farrell believes the All Blacks are the best.
"This is a side that has been top of the tree for nine years, and let's be fair, it's been longer than that really," he said about New Zealand.
"There's only one team that is top of the tree.
"But it's an important year (for Ireland). It's important for us to keep building and keep trying to close that gap."
Assistant boss Farrell is firmly in Irish Rugby Football Union (IRFU) minds as a replacement for Joe Schmidt should the head coach opt to return to his native New Zealand after next year's World Cup.
Leinster coach Stuart Lancaster is on the IRFU radar to step into the Ireland set-up too, leading to the possibility of Farrell linking up again with his former England colleague.
Farrell neatly sidestepped the issue on Tuesday, insisting he would be foolish to address such talk when preparing to face the All Blacks.
Asked to comment on whether he could step up as Ireland head coach in time, Farrell replied: "Thank you very much! Look, that type of thing, you won't expect me to answer that today in the week that we've got.
"What I would say on that is that I have a fantastic job, I really enjoy myself working under Joe, learning.
"Joe will make his decision in time, I'll keep enjoying myself and hopefully keep getting better."
