Willey produced a strong bowling performance, taking three for 69 from his 10 overs.
The Northants man claimed the scalps of three of the New Zealand top four, with Martin Guptill, Kane Williamson and Ross Taylor all falling to Willey.
But by the time Williamson and Taylor departed, having hit 118 and 110 respectively, the Blackcaps were well on top.
And they got home to secure a three-wicket win, meaning they now lead the ODI series 2-1.
Willey had plenty of reasons to be positive though as he followed up a wicket-taking debut in Ireland by earning recognition for a trio of dismissals.
And the 25-year-old will now hope to be involved again when England face New Zealand on Wednesday.