England 191 for 7 (Root 68) beat New Zealand 135 (Williamson 57, Willey 3-22, Wood 3-26) by 56 runs
Scorecard and ball-by-ball details
England continued their remarkable resurgence in limited-overs cricket with the third largest victory in their history over New Zealand in the one-off T20 at Old Trafford.
England had won only three of their previous 12 T20 matches and, in that period, suffered a defeat to Netherlands. But inspired by their young players - there were three T20I debutants in this side - and a newly acquired aggressive approach, they followed the 12th highest total in their T20 history, and the fifth highest in England, with a disciplined display of bowling that eventually saw New Zealand lose their last five wickets for the addition of just four runs in 12 legitimate deliveries.
Only 11 times have they been bowled out more cheaply in a T20. Their captian, Brendon McCullum, rated their batting as "pretty amateurish."
The result, an England win by 56 runs, means that a New Zealand side that were thought by many to be the strongest to have toured the UK depart without a series win in any of the formats. They were previously held to a draw in the Test series and lost the ODI series.
When they cruised to 89 for 2 in the ninth over with Ross Taylor and Kane Williamson together, it seemed New Zealand were on course for victory. Jonny Bairstow, deputising with the gloves for the injured Jos Buttler, had just missed a simple opportunity offered by Taylor off the unfortunate Ben Stokes and Williamson was batting with the class and composure that has become his trademark.
But then Taylor miscued an attempted lofted drive and, while Williamson went on to compile the second half-century, and highest score, of his T20I career, nobody else could reach double-figures.
Mark Wood, one of England's debutants, finished with three wickets - doubling his career tally in the format - as reward for his pace and full length, with David Willey, another debutant, also claiming three wickets as reward for his control and yorker length.
By the time Williamson, called for an optimistic single by Nathan McCullum, was run out by an outstanding pick-up and throw from Willey, with one stump to aim at, from cover point, New Zealand were doomed. The last three batsmen failed to score.
It was an impressive performance in the field from England. Willey, finding some late swing, claimed the wicket of Martin Guptill in the first over of the reply with a beauty that pitched on off stump and nipped back to hit leg, while McCullum's early assault - he crashed four sixes and two fours in his 15-ball stay - was ended by a fine piece of bowling from Wood who, spotting the batsman giving himself room, went wide of the crease and followed McCullum with a yorker-length delivery. McCullum could only edge it on to his stumps.
Earlier Joe Root sustained his excellent form with another half-century. Striking the ball with a power that belies his relatively willowy frame, he combined innovation with convention to put England on target to a substantial total. Starting with a rasping cut to the boundary, he showed a willingness to hit over the top, an ability to execute the reverse sweep against balls even outside leg stump and his now established ability to pick up the length unusually fast.
At one stage England took 23 from a Nathan McCullum over with Root pulling two fours before Sam Billings thrashed two fours and a six off the final ball full toss.
Given a bright start through Alex Hales and Jason Roy, who drove two sixes over long-on in Mitchell McClenaghan's first over, they stuttered in mid-innings when Bairstow was bowled by a beauty from debutant Mitchell Santner, who produced a fine spell, that gripped and turned past his outside edge to hit the top of off stump and Eoin Morgan miscued to deep midwicket.
But Stokes added late impetus and, with New Zealand starting to look weary at the end of a long season, took England to a total that proved more than enough.
George Dobell is a senior correspondent at ESPNcricinfo