Jos Buttler was left to reflect on a squandered opportunity as a missed run out cost England dear against New Zealand. The Black Caps have called up left-hander Henry Nicholls as back-up for Williamson. Beating Australia in the next match will put them in the final.
If New Zealand beat Australia at Eden Park on Friday night, the two will meet again in the final on the same ground next Wednesday.
Both skippers shrugged their shoulders at the toss, beside a frightening looking drop-in pitch with half of it bereft of grass.
Williamson's comments come after former New Zealand pace bowler Simon Doull questioned whether the 27-year-old and head coach Mike Hesson should be part of the Black Caps' Twenty20 set-up.
England: IN: Liam Plunkett, Mark Wood.
The Kiwis are likely to give debuts to two players after wicketkeeper Tim Seifert and ex-Hong Kong batsman Mark Chapman were added to the squad in place of Tom Blundell, Tom Bruce and Seth Rance. Having won every game at home this summer until two T20 defeats to Pakistan in January, they will be hoping to get back on track.More news: Intelligence chiefs deliver warning on Russia
This was his day.
Williamson, who's been under pressure after several ineffectual knocks in T20 internationals, was lucky not to be run out on the first ball he faced. Chapman, now a dual global, became the first player born in Hong Kong to play for a full member side since Dermot Reeve's England debut in May 1991.
After a few sighters he morphed into Chris Lynn, swinging hard and sending four soaring into the crowd including back-to-back sixes off Wood, clubbed over the leg side.
Opener Guptill raced to 65 off 40 including three sixes while captain Williamson accelerated late in his 72 off 46. Debutant wicket-keeper Seifert hit 2 sixes in the last over as New Zealand finished the innings for 196 for the loss of 4 wickets.
England's bowlers were relatively loose, with legspinner Adil Rashid (2-36) and speedster Mark Wood (2-51) the most successful.
Opener Jason Roy went for eight but Hales and Malan put on the kind of display which looked like being the launchpad for an important victory. However, one of them, Colin Munro, has been in awful form recently, and his reliability is uncertain. Mitchell Santner is another one with a knack for breaking partnerships.
He kept swinging but Buttler was the big one. England's match in Hamilton against New Zealand on Sunday would then be embarrassingly meaningless.