After the mercurial opener set the hosts on course for a total of 194-8 at Seddon Park, the fast bowler led an attack that dismissed the tourists to seal a 21-run victory on Sunday night.
It was the Black Caps’ second impressive win of the weekend, following their 46-run triumph on Friday night, and took them within one game of clinching the five-match series.
Allen lashed 74 runs from 41 balls - his third-best score in T20 internationals - in an explosive start that established a base of 122-1. New Zealand couldn’t quite capitalise, however, as Kane Williamson retired hurt with hamstring tightness and Allen’s wicket was part of a 6-46 slide.
But after a couple of bad drops in the field left Pakistan well placed on 97-2 in their chase, Milne’s express pace helped him snare 4-33 - his third-best T20I figures - as the target remained out of reach.
It was a similar pattern to the first match on Friday night, with Pakistan having again asked the Black Caps to bat.
That seemed an unwise decision when Allen lost a ball with a prodigious pull in the second over, before putting another into the crowd to end the third and smacking a third six in the fourth.
But Aamir Jamal dismissed Devon Conway (20 off 15) off a leading edge in the fifth over, extending to 15 innings the opener’s run of failing to reach 50 across all formats.
The Black Caps ended the powerplay on 65-1 - having been 56-2 en route to a record total at Eden Park - before Allen raced to his half-century from 24 balls. Williamson (26no off 15) was again looking in fine touch to lift his side to 111-1 at the halfway mark, but during the drinks break left the field as a precaution and failed to return.
That saw the innings stutter as Allen fell to Usama Mir in the 13th over, having deposited the spinner for his fifth sixth the previous ball, and game-one star Daryl Mitchell departed for 17 off 10.
The run rate slipped as Mark Chapman holed out cheaply before Glenn Phillips and Milne were dismissed off consecutive balls from Haris Rauf (3-38). But a key cameo from Mitchell Santner (25 off 13) made for a timely return from Covid - and a testing total for Pakistan.
The Black Caps then gave their opponents a helping hand. After Tim Southee and Milne removed the openers in the first two overs, Ben Sears was initially at fault when he dropped a sitter to give Fakhar Zaman a life on zero.
Chapman then did likewise with Babar Azam on 27 - this time with Sears at the bowling crease - and that pair proceeded to make the fielders pay.
The Pakistani duo put on a match-high 87-run stand from 49 deliveries for the third wicket, feasting particularly on the opening overs of spinners Santner and Ish Sodhi.
Zaman (50 off 25) smeared five sixes but, two balls after registering a half-century, Milne had him chopping on as Pakistan were reduced to 97-3 at halfway, needing a further 98 off 60.
Sears (2-28) soon atoned for his error with the wicket of Iftikhar Ahmed, while Sodhi (2-33) fought back well by having Azam Khan caught on the boundary and getting Aamir Jamal stumped with the googly.
Pakistan lost 4-28 and went 26 balls between boundaries as the required rate swelled above 12, before Sears induced a fault shot from Azam (66 off 43) to begin the 18th over and essentially seal victory.
