There was a groan around Seddon Park when Brendon McCullum won the toss and asked Bangladesh to bat. As Trent Boult hooped the new ball the signs were it could follow a familiar pattern as New Zealand's earlier successes, but this time the script was not pre-written and provided the co-hosts with a set of challenges they have not faced in the tournament.

They were required to change the team due to an injury; took limited new-ball wickets; came under pressure at the death; bowled a full fifty overs; had two in-form batsmen go early; faced quality spin; and were left with two bowlers to finish off the chase. The fact that list was so long highlights, with the exception of the collapse against Australia, how blemish-free the group stage has been.

Not every question asked of them was answered as emphatically as they would have liked - especially the late dismissals of Luke Ronchi and Corey Anderson in a messy finish - but each facet of their game has now been tested ahead of the quarter-finals. Martin Guptill has the team's first hundred and the middle-order showed some punch. Unlike the Australia match, there was no top-order batsman present to seal the chase but hefty blows from Daniel Vettori and Tim Southee were enough.

"It just shows you we found another way in a game," Southee said. "That's testament to the side, we were challenged in different ways and were able to come through it. It shows the qualities of the side that we can win in different circumstances.

"All the guys learnt from the Aussie game and the pressure that comes with an nervous run chase. The bowlers work extremely hard on their batting in the nets. There's a lot of faith in us so it was nice to repay that for the batsmen."

The first issue New Zealand had to confront was before a ball was bowled. They have steadfastly stood by their first XI during the tournament, which is understandable given the results, and they would not have changed here if they had not been forced to.

The performance of Mitchell McClenaghan, who replaced Adam Milne when his shoulder did not recover in time, showed the other side of the balancing act between continuity and ensuring players have middle time. He bowled like a man who has not played for a month, initially whipped out of the attack after one over which went for 11 then bowled in two blocks of four, and numerous times could not stay on his feet - although that is not a new issue for him.

In his 35-match ODI career, during which time he was joint second-fastest to fifty wickets, he has shown his expertise at the death but this time, through rustiness and the pressure applied by Bangladesh, struggled to stem the tide in the final ten overs. There is only so much that bowling in the nets, day after day, week after week, can replicate. By Milne being sidelined for this game it means he now will not have bowled in the middle for nearly two weeks come the quarter-final, but this was not a display from McClenaghan to prompt any late changes to the favoured first XI.

There were also some curious tactics by McCullum as the innings came to a conclusion with McClenaghan's remaining overs not fitting what were left in the innings, meaning Elliott bowled two of the last three overs. On a day where he was expensive sharing McClenaghan's overs was understandable, but McCullum left it late. New Zealand insisted it was not a miscalculation, just an extension of McCullum's attacking instincts. The final ten overs cost 104, not carnage compared to some matches in this tournament, especially in Australia, but the fiercest treatment New Zealand had felt.

Recent history favoured New Zealand in their chase - last year they hunted down 279 against India with considerable ease - but the promised early foray by spin from Bangladesh provided handsome rewards. McCullum's ultra-aggressive approach has carried his team, both in runs and in spirit, but this was one of those occasions when his dismissal, picking out long off, felt like a waste.

A waste then became an aberration when Kane Williamson, who was laid low with a sickness bug in the lead-up to this game, cut to point. At 33 for 2, and an uncertain Ross Taylor at No. 4, the challenge was laid.

Guptill, who opened his scoring with two sixes off Shakib Al Hasan, rose to it with his sixth ODI hundred and New Zealand's first of the tournament. There was a tight lbw shout on 19 and an edge wide of the keeper on 68, but his timing and placement was otherwise immaculate.

"Today was one of those days when everything went in the gap and I scored quite freely," he said. "Those days are few and far between sometimes so when you have them to need to make the most of it. I always felt I've been around the corner through the whole summer. It was nice everything clicked."

Taylor was less convincing, and does not suggest a player full of confidence, with his 56 off 97 being his slowest 50-plus score in ODIs. But the stand of 131, which was New Zealand's highest of the tournament, proved a solid riposte to the early setbacks.

"Brendon and Kane are having good summers, but them getting out early and us able to put a hundred stand on - myself and Ross - then Grant coming in with the great cameo and Corey as well, just shows the depth we've got in the line-up and can fight in any situation," Guptill said.

Either Taylor, Elliott, or Anderson should have finished the chase and in the end it was left to Southee to strike the final blows of New Zealand's group stage clean sweep. A day that began with groans ended with cheer. There has been plenty of it so far. Now an era-defining two weeks looms.

Andrew McGlashan is a senior assistant editor at ESPNcricinfo