Allrounder Devine has been a dominant forced in the ODI and T20 series and it was no different on Thursday as she blasted 70 off 44 balls at the top of the order.
A 116-run opening stand with captain Suzie Bates (52 off 43) was the backbone of New Zealand's 150-8 before the hosts were restricted to 111-7.
The White Ferns, who won the ODI series 2-1, move 2-0 up in the four-game shorter format series with matches remaining on Sunday and Tuesday.
Pakistan must find a way to handle Devine, who blasted five sixes.
She has scored 278 runs in rapid style across the five tour matches.
New Zealand's innings crumbled after the openers departed, somehow losing six wickets in the space of nine balls at one point.
A sluggish start to their chase meant Pakistan never threatened.
Amy Satterthwaite (2-18) and Bates (1-13) bowled three overs each and returned the best figures.
Holly Huddleston (1-20) bowled her full complement and impressed with the new ball.
