Hales (80no) and Lumb (53no) hit nine sixes between them as England made a nonsense of New Zealand's 139 for eight, overhauling their target with more than seven overs - and 10 wickets, of course - to spare at the Westpac Stadium.
"All round, it was probably the most powerful performance I've seen from an England (Twenty20) side really," Broad said.
The Nottinghamshire pair, surplus to requirements for the one-day international series which begins in Hamilton on Sunday, therefore signed off in spectacular style. Their unstoppable hitting resulted in England's highest opening partnership in the sprint format, and the second-best for any wicket.
England, however, could have felt confident even before their openers got going that they had an outstanding chance of completing the 2-1 series victory - after Broad himself had led from the front in a highly-impressive demonstration of collective talent with the ball and in the field.
Only opener Martin Guptill (59) provided any substance for the hosts - and, albeit on a pitch which characteristically improved for batting in the second innings, his tally of one six and two fours paled in comparison to Hales and Lumb.
Broad added: "The result, and the way we adapted to the conditions with the ball, was brilliant. The fielding was strong as well, catches being held. It was a pretty perfect performance really."
Hales and Lumb then merely emphasised England's superiority, and suitably impressed their club-and-country team-mate Broad in the process.
"We know early wickets 'kill' you in Twenty20," he said.
"So it was great to see the guys take their time and get used to the wicket a little bit for two or three overs ... then once Alex Hales got going, it looked hard to stop him. Some of the sixes were huge. Lumby's almost went out of the ground to finish the game."