"They bowled brilliantly at the start with good pace and put us under pressure. It's testament to the way Kane and Corey [Anderson] played that we got as close as we did. I thought Corey did a great job [on ODI debut after three T20 appearances in South Africa] with limited opportunity. He showed encouraging signs. For a little while, I thought they were going to get it done."
Williamson (67 off 54 balls) and Anderson (30 off 24 balls) put on 73 for the sixth wicket. It was a heroic rearguard action after the team slumped to 62 for five in the 14th over.
"When we needed 10-an-over I knew we were in it," Williamson said. "It was a shame we lost wickets at key times and couldn't clear the rope. We gained momentum and lost it."
Williamson's dismissal was the turning point. Debate surrounded whether bowler Stuart Broad's foot had been behind the popping crease when the New Zealander hit a steepler to cover. A no-ball check said it was, but it was far from definitive.
"It was close but we didn't have problem with benefit of the doubt to the bowler," McCullum said.
England captain Alastair Cook was equally ambivalent: "Broady said it might be close. I did not realise it was quite that close. It looked like there was a part of his foot landed behind the line on the big screen and then he pushed forward. Both sides probably saw it differently. I think on those decisions you have to go with the umpire's call. If he had given it as a no ball I don't think we could have many complaints."
Cook's 64 off 47 balls, from a player seldom used in the T20-style format, was a revelation.
"I found it hard knowing what a good score was. Maybe we set ourselves too high a target at 180-190 because we lost seven wickets for 36 runs. It's important you strike early when you are defending 170 and the first four overs was fantastic bowling from Jimmy [Anderson] and Broady. Obviously it was a good partnership from Anderson and Williamson but we felt in control. With a small boundary [to one side] there was always the chance he could go berserk at the end. Twenty-four overs can be a nerve-racking time for a captain."
Ross Taylor's dismissal, using the team sole decision review after being adjudged lbw to Tim Bresnan at the end of the seventh over, exposed the middle order without insurance. The way Taylor instantly chose to review gave the impression he must have hit the cover off it. He hadn't.
McCullum was fine with his call: "It was definitely an option, both were 'umpire calls' [on the DRS] hitting outside and going over. That tells me it was worth reviewing."
Equally McCullum didn't blame older brother Nathan for dropping Cook three times on 14, 37 and 45, despite taking four catches in total.
"The ball kept following him around. He's a brilliant fielder and today he dropped a couple but he's still up in terms of fielding ability. I won't begrudge him for that."
New Zealand is now left to observe Australia against Sri Lanka with interest.
"We'd love Australia to play some excellent cricket tomorrow, but obviously not too good," McCullum quipped.
