
New Zealand require 266 runs to secure the series victory.
Shanto hit 105 from 119 deliveries and shared a critical 160-run partnership with wicketkeeper Litton Das, who scored 76, after the home side stumbled to 32 for three inside the first nine overs.
Fast bowler Will O'Rourke caused the initial damage for New Zealand. O'Rourke dismissed openers Saif Hassan and Tanzid Hasan for zero and one, respectively, before removing Soumya Sarkar for 18, finishing his seven-over spell with figures of three for 32.
Following the sharp opening burst, Shanto and Das absorbed the pressure and initiated a controlled recovery.
The pair relied heavily on strike rotation and gap placement during their 178-ball stand rather than regular boundaries. Left-arm spinner Jayden Lennox eventually broke the partnership by dismissing Litton Das in the 39th over, and later claimed Shanto to finish with two for 50.
In the lower-middle order, Towhid Hridoy provided late acceleration, remaining unbeaten on 33 from 29 balls. Captain Mehidy Hasan Miraz added a brisk 22 from 18 deliveries before falling to off-spinner Dean Foxcroft.
The New Zealand bowling attack maintained discipline during the death overs, restricting Bangladesh to 34 runs in the final five overs while taking three late wickets, reports UNB.
Fast bowler Ben Lister secured two of those dismissals in the 49th over, removing Shoriful Islam and Tanvir Islam in quick succession, finishing with two for 62.