Devine smashed 93 off 41 balls as New Zealand raced to their target with 35 overs and eight wickets to spare.
Earlier, seamer Hannah Rowe had starred with the ball, taking 3-22 as Pakistan were bowled out for 144.
New Zealand's next match is against hosts England at Derby on Wednesday.
In Saturday's other match, South Africa beat India by 115 runs.
Proteas opener Lizelle Lee hit seven sixes in her 65-ball 92 to lay the platform for a total of 273-9.
India were never in the hunt and slumped to 158 all out - Dane van Niekerk taking 4-22.
The result means England drop out of the top four - the qualifying spots for the semi-finals - before Sunday's clash with Australia.