An Indian cricketer once told me that the singing of the national anthem before battle commenced on the field helped in finding focus. Watching the New Zealand team at this pre-match routine on Saturday was to feel their energy radiate through the ground.

West Indies did their job with due reverence - and theirs isn't really a national anthem - standing solemnly, hands clasped together or hanging at their sides, some looking down, some up, and when it ended, they all relaxed. New Zealand, however, made a statement. As soon as the West Indian anthem ended, the New Zealanders' arms went up and around the shoulder of their mates on either side, drawing each other together so tight there was no daylight in between. And there they were, a group of powerfully built men in their black kit (in itself a statement of authority) standing tall in solidarity, like a band of brothers, with a tribal energy about them. It was an arresting and powerful image, a visual representation of their World Cup campaign.

It would be simplistic and perhaps misleading to infer too much from this. But taken in isolation, the two images would tell not too inaccurate a story. New Zealand's wall represented an irresistible force forged from shared belief and purpose. West Indies were a group of individuals brought together for battle.

New Zealand is a rugby country, unmistakably. The Regional Stadium in Wellington is a rugby stadium dressed up for the cricket World Cup. The images around the stadium are of rugby players, and even of rock and pop bands, because they host concerts here. But inside the elevators that bring you to the media centre and the corporate boxes, there's a photograph of Brendon McCullum walking out to bat. You can see only his back, with his name printed on the jersey, but even if it wasn't, you would know who it is. His bat is loose in his left hand, and he is walking through a sea of New Zealand flags and outstretched hands. He looks gladiatorial. It tells two stories at once: of how a rugby nation has thrown its soul behind cricket, and of how McCullum has built a team in his own image.

Coming into this quarter-final, New Zealand had reached six World Cup semi-finals but won only one knockout match - against perpetual underachievers South Africa in 2011. Almost every one of those semi-finals had felt like an overachievement. Barring 1992, when Martin Crowe had led them with imagination and passion, the end of their journey each time had seemed appropriate. But this time, from the first match, from the very first over, with bat and ball and in the field, they have sought to impose themselves, to set and control the pace of each match.

Being the favourite in a knockout game, though, carries its own burden. Only once in this World Cup before this game - in the match against Sri Lanka - had they gone about setting a target, and only once had their batting been tested in a big chase, and that was in an inconsequential match against Bangladesh. That went to the last couple of overs. It raised several questions. Were New Zealand too reliant on their bowlers? Could they find the momentum without McCullum's fiery starts? Had their middle order been tested enough? And what about the fifth bowler?

About the first question, New Zealand didn't want to die wondering. On winning the toss against West Indies, they embraced the challenge by going against their conventional mode of winning in this World Cup. Bowling had been their bigger strength, but in perfect batting conditions and against a team carrying one genuine wicket-taker, it made cricket sense to reverse the pattern. No one would have blamed McCullum had he stuck to the winning formula, but safe choices are not always the best ones. It would have gone against McCullum's grain.

New Zealand found themselves confronted with the second and third questions quite early. McCullum fell in the fourth over, for 12 off eight balls. Then Kane Williamson, the man expected to steer the innings to safe waters, had a bright innings cut short by a ball that stopped on him. They now had two batsmen in with runs behind them from the Bangladesh match and not a lot more from the rest of the tournament. Martin Guptill, in fact, had carried the worst-possible form into the World Cup and Ross Taylor had been scratchy.

The run rate was healthy but not spectacular and, in this must-win match, New Zealand now required building and accumulation towards a final charge in setting up a target. For a campaign built on sustained aggression, the situation demanded sensible and pragmatic batting. Guptill finished spectacularly, with an avalanche of fours and sixes, but Taylor's role in building the case cannot be understated. The bowling wasn't threatening, but New Zealand needed to prove, to themselves as well as their opponents, that they could find a gear other than sixth when circumstances mandated.

Only the last question remains unanswered. Trent Boult's superhuman effort - once again he bowled ten overs on the trot - ensured that West Indies were not in the contest when he finished. The six overs bowled by New Zealand's fourth and fifth bowlers went for 66. But as they savour their rightful place in the semi-final, New Zealand are likely to treat that as another challenge rather then fret over it. Their march in this World Cup has featured spectacular individual performances, but New Zealand haven't departed from the familiar theme of the collective.

In fact, they have taken it to new heights. When a ball caught the shoulder of Marlon Samuels' bat and lobbed over the catching cordon, five men - three slips, a gully and a backward point - chased it all the way. It looked exaggerated and unnecessary, and it looked like New Zealand were making a production of it. But it was not an aberration. They have done it all through.

It was certainly not an aberration that the oldest man among the chasers, Daniel Vettori, got to the ball first. He later held a catch so spectacular - leaping and pouching the ball with one hand behind him a couple of feet from the fence - that Samuels, the batsman on the receiving end, spent a couple of minutes mid-pitch to reflect on the unfairness of it.

Anything is possible with this team now.