When told concerns voiced by the likes of former South African great Shaun Pollock over New Zealand's batting capability beyond No 3 Kane Williamson, McCullum responded: "We'll see.
"The nature of how we've played games of late, and being able to have success bowling first, has meant the batting hasn't been as challenged as other teams in the competition.
"We'll never know until we get in those situations, but I'm confident the guys we've got are very good players, and very good under pressure. And we'll see how that stands up in the coming weeks."
Plan A is working splendidly for New Zealand so far and McCullum confirmed it will be full steam ahead again today with a forthright approach.
"We'll still try to operate the same way. That's a style that sits well with us. We feel it gives us our best possible chance.
"The aggressive, or positive, mindset we're going into games with is not always going to work, but it's the best method of play for us and we'll continue to play like that."
Allrounder Corey Anderson took a painful blow on a hand during fielding practice yesterday, but continued taking a full part in practice and is expected to take his place in the side today.
Afghanistan coach Andy Moles, former coach of New Zealand, is a forceful advocate for his new team.
Their first appearance at the World Cup was always going to be a challenge, but they've nailed their first win (over Scotland) and had a royal chance of a second (over Sri Lanka), but got a serious touch-up from Australia in Perth on Wednesday.
"They are very passionate, proud people and their history back home shows they're full of fight," Moles said. "We have come a long way in a short time. We know we're in for a tough examination tomorrow but we're looking forward to putting our best foot forward."
Moles said there was a pile of positives to take out of the tournament and serious learnings to be gained from playing top-class opposition in a range of conditions.
They have three bowlers -- Shapoor Zadran, Dawlat Zadran and Hamid Hassan -- who deliver at 140km/h and present distinctly different challenges. Samiullah Shenwari, who oversaw the win over Scotland in the closing overs, is by some distance their most accomplished batsman.
Consistency is a quality they are striving for.
Talks are taking place with "four or five" countries about more access to international opponents. They need it, but this has been an encouraging opening step.
After New Zealand, they face England in Sydney on March 13. Given England's woeful form, Afghanistan might fancy their chances.
Today should be well beyond them but McCullum insists they'll be respected.
Given their history, resilience and sheer exuberance for the game, they deserve nothing less.
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