Spinner Daniel Vettori underlined the importance of his side's slow bowling after the 129-run win over Ireland.
Vettori claimed four wickets as Ireland fell apart late on
Vettori took four wickets in a late spell that saw Ireland lose their last six wickets for just nine runs.
Vettori said: "It's nice to see spinners playing an important role and it's good to see us playing two.
"I'm not a big spinner of the ball, so I mixed up my pace and used some drift. Hopefully I can carry this form into the big matches we've got coming up."
New Zealand recovered from a slow start to post 263 after winning the toss and choosing to bat.
Vettori said: "It wasn't too bad for batting, and in the end we managed to get a decent score on the board thanks to good works from James Franklin and Brendon McCullum.
"260 was always going to be tough for them, but we still managed to turn the screw and get the result."
It wasn't until the last four or five overs that we stamped some authority on this game
New Zealand captain Stephen Fleming
Captain Stephen Fleming also admitted his side had struggled at times during their innings.
"Up until 40 overs we felt we were behind," he explained.
"Ireland put pressure on us and we weren't good enough to get partnerships through the middle.
"Today we were a little bit hesitant or over-aggressive and what it did was create some pressure and anxiety as the batsmen went out and Ireland capitalized on that.
"It wasn't until the last four or five overs that we stamped some authority on this game."
New Zealand now look well set for a place in the semi-finals, although they now face Australia, South Africa and Sri Lanka in the space of just six days.