Williamson might have considered himself unlucky to get out. There was significant doubt as to whether bowler Stuart Broad's foot had been behind the line when Williamson hit a steepler to cover. A no-ball check said it wasn't.
Williamson and Anderson gave New Zealand a whiff of hope with a series of classical strokes. There was even a dramatic delay, one ball into the 20th over which, upon completion, gave the match official status. Anderson appeared to strain his right calf muscle. After a delay of several minutes he was back and, as one press wag noted, was running "like a gazelle".
Three key moments worked in England's favour during New Zealand's spirited chase.
The first was James Anderson's delivery to Williamson which started the sixth over. The master of swing got a ball to jag back about half a metre from outside off stump. The delivery created enough hesitancy to have the New Zealanders cautious for a few overs. It suggested what had previously been a good batting pitch might hold demons in the second innings.
Ross Taylor's dismissal, using up the team sole decision review on lbw to Tim Bresnan at the end of the seventh over, exposed the middle order without any insurance. The way Taylor instantly chose to review gave the impression he must have hit the cover off it. He hadn't.
Finally, Brendon McCullum, forced to play cautiously coming in after Taylor at 27 for three, swung the first vaguely loose delivery he could off Ravi Bopara into the air on the legside, only to be caught by sweeper Joe Root. It was a case where the purpose-built grounds came to the bowler's aid through longer square boundaries.
Curiously in such an abbreviated format, New Zealand's side was more similar to their T20 team personnel than England's. The pivotal innings of the game - Alastair Cook's 64 off 47 balls - came from one of England's least likely T20 contenders.
Earlier, New Zealand fought back against an England onslaught.
England accelerated to be 141 for three in 18.3 overs on what appeared a good batting wicket after they were sent in. The innings included the rare sight of Joe Root clobbering Daniel Vettori over the mid-wicket boundary when the left-armer dropped short.
However, England lost their last seven wickets for 28 runs in 30 balls. Limited overs coach Ashley Giles was sighted looking pensively at his 1B5 exercise book.
New Zealand endured a horror spell in the field, including Nathan McCullum dropping Cook three times. McCullum redeemed himself with four catches, including Cook caught and bowled, on what will soon be his home ground when he takes up a Twenty20 contract at Glamorgan.
Fortunately brother Brendon set the standard early, catching a full-blooded Ian Bell drive at short cover, before the team's spate of sloppiness took hold.
Mitchell McClenaghan continued his assault with the ball taking three for 36 off five overs. He has 11 wickets from three matches in the tournament at an average of 13.09. He has struck every 13 balls.
Kyle Mills had the best figures of four for 30.
Anderson replaced Tim Southee in the New Zealand XI who was rested with an ankle twinge. He was a late addition to the squad. The 22-year-old replaced Grant Elliott who aggravated his calf muscle injury at training yesterday. Anderson's previous international experience was three Twenty20 internationals in South Africa.
