Phillips, batting at number 4, scored a monumental 107 from just 49 deliveries that included six fours and 10 sixes, while Michael Bracewell smashed 65 off 25 balls as the Blacks Caps amassed a total of 259-7, their highest T20I total at home.
India's bowlers toiled with none of the visitors' seven bowlers going for under nine runs to the over, although Mayank Yadav did take three wicketsfor 48 runs in four overs.
Duffy then put India under the skids in the run-chase with figures of 4-23 in his fours overs, as the tourists were restricted to 172-9 after 20 overs.
The seamer was well supported in the field, with Matthew Fisher and spinner and home skipper Mitchell Santner took two wickets apiece.
India have won the five-match series but New Zealand pull another game back when the fifth and final match is played in Hamilton on Sunday.
New Zealand's bowling unit fought hard to defend a low total but India came out on top by four runs (DLS method) in the second ODI in Wellington as the visitors went 2-0 ahead in the five-match series.
New Zealand fast bowler Jacob Duffy believes Virat Kohli remains one of the most difficult batters to contain, after witnessing the Indian star produce a match-winning performance at Eden Park.
Arshdeep Singh took four wickets before Virat Kohli hit 74 as India beat New Zealand by five wickets in a rain-affected first of five ODIs that was played in Auckland on Wednesday.
New Zealand batter Devon Conway has been ruled out of the first ODI against India after he took a blow to the head after colliding with teammate Matt Henry during training.
