Who will seize this moment?

A tournament that runs for six weeks and includes 49 matches seems like it should be about build up and progression but is actually about much less. Or much more, depending on how you look at it. When it gets to where this World Cup is now, it is about moments. Big moments, but moments nonetheless.

Moments like Brendon McCullum's, when he put his front foot forward and drove the final ball of the first over of the tournament for four against Sri Lanka in Christchurch. With that one shot, McCullum revealed his team's attacking approach. They have not stopped since.

But it took another 13 of those moments, four of which belonged to Martin Guptill, to show why that was a sound strategy. By then, New Zealand had posted an opening stand of 104 and untied the ball of nerves that had formed over several weeks of preparation. Some would have wondered if New Zealand were good enough, others whether they were capable of showing how good they really were with the burden of carrying an expectant home crowd with them. Those opening moments answered those questions.

South Africa did not have a moment similar to that until Dale Steyn dismissed Tillakaratne Dilshan in the quarter-final. In that moment, with fire in his eyes, fury from his mouth and a committed fielder at his side, Steyn silenced the scornful sounds that have been made about South Africa at major tournaments. It was never about whether they were good enough, always whether they wanted it enough and whether their minds were strong enough. At this tournament too, South Africa had given people a reason to wonder about those two things.

They were overawed by the moments against India long before those moments even arrived. When they got to the MCG, the madness of the moment engulfed them. India had lain dormant throughout an entire summer, saving up to string together moments at one tournament and South Africa ran into the sleeping giant just as it had begun to stir.

Once they'd shaken off that moment South Africa went on to snatch others that were readily available. AB de Villiers greedily gobbled up the moment against Jason Holder when he could take South Africa to over 400 against West Indies, Faf du Plessis did it against Ireland. What mattered more was the moment against Pakistan and when South Africa botched that with a familiarly muddling middle-order performance, it was thought their moment had passed.

That was the only game of the pool stage where South Africa were caught in a maze of pressure but they did not take a moment to figure out how to get out. Instead, they followed one moment of madness with another and in the worst moment of all, their captain said he had "nothing good to say" about them that day.

That moment, where de Villiers went from disappointed to dangerously angry, was the moment South Africa found life in the tournament. They still had ten days and another game but they had been warned that failure to seize the next moment would not be acceptable. They mulled about and went through the motions but when the time came to make the moment their own, they did. It was in the fifth over of their quarter-final clash.

New Zealand had more of a multitude of moments. Tim Southee punctured England, not in one moment, or two, or even three but seven times just to be sure. Or Kane Williamson struck the six that sealed victory over Australia in a game where New Zealand owned almost all the moments but Australia threatened to steal the most important one.

They had moments of control - when Ross Taylor became the fastest of his countrymen to 5000 runs despite a strike rate which has been lower than his team-mates' for much of the tournament - of courage - when Grant Elliott smacked the second ball he faced in the Bangladesh game for four to keep New Zealand steady - and commitment - when Daniel Vettori arched himself into a parabola to take the catch that dismissed Marlon Samuels in the quarter-final. Guptill had moments of all three of those things in his innings on Saturday, the likes of which the World Cup has never seen before.

Both South Africa and New Zealand have let moments pass them by at every World Cup they have played before this one. Over the last five weeks and 14 matches they have got some of those moments back. New Zealand have done it by keeping a clean sheet, South Africa by making history with their first-ever victory in a knockout match in a World Cup. Now both of them will know they need to turn up for their biggest moment yet.