Two young men, both scraggily bearded, embraced as they stood on the boundary at Eden Gardens' Pavilion End on Wednesday. The easy conversation between them continued, replete with smiles and knowing looks, as they walked to the middle. There they stopped and waited for the formalities to be completed, talking to each other all the while. Clearly, they were on the best of terms.

One of them sent a coin tumbling into Kolkata's thick, hot evening air. The other called, and the first act of the men's T20 World Cup semifinal between New Zealand and South Africa was complete.

Mitchell Santner and Aiden Markram are, by all accounts, bloody good blokes. But did they have to be so friendly with each other before the toss? It looked less like the prelude to a high-profile match of massive consequence than two mates enjoying a fat chat while they strolled to their favourite pub.

Maybe this was just another cricket match after all. That's what it looked like when Markram dinked the first ball, bowled by Matt Henry, who was fresh off the plane after going home to be with his wife Holly at the birth of their second child, to midwicket for a single.

Then Cole McConchie had Quinton de Kock and Ryan Rickelton caught with consecutive deliveries, both thanks to ragged strokes. At 12/2 after 11 deliveries, it was as clear as the air was not - this was not just another cricket match.

At least, not of the kind of match the South Africans had played to make it this far in the tournament. They had more than a hundred runs on the board when their second wicket fell against Canada, Afghanistan and the selfsame New Zealanders, were 56/2 against the United Arab Emirates, and lost only one wicket against West Indies. But they were also 12/2 against India, and 14/2 against Zimbabwe. They won all of those matches. And that despite slipping further to 20/3 against India. But that was then. This was now: when it mattered.

Dewald Brevis joined Markram, and edged McConchie's hattrick ball for four. Then Rachin Ravindra, at midwicket, dropped a catch he should have taken - and that would have dismissed Markram for 3 and reduced South Africa to 22/3.

Markram smoked Lockie Ferguson's next ball through the covers for four with imperious power. South Africa's captain followed that with a hoist over midwicket for six off Jimmy Neesham, who was cover driven for consecutive fours by Brevis to end an over that went for 17.

Not before time, the South Africans remembered who and what they had been in this competition. But, in the eighth, with the stand worth 43 off 35, Markram hammered Ravindra high towards long-on. Daryl Mitchell came screaming in, tumbled forward, and came up with the dipping ball. Had he caught it? He gestured that he wasn't sure.

The decision was sent upstairs, and replays suggested the ball had hit the ground before Mitchell had securely curled his fingers under it. Nitin Menon said otherwise. Finn Allen's mouth gaped in disbelief when the verdict was handed down on the big screen. Markram trudged off, his face twisted into a scowl that pushed his smiling stroll with Santner far back in the memory.

Sixteen deliveries later David Miller and Brevis had also been dismissed - both thanks to loose drives - and South Africa were 77/5. Just to make things more challenging, Tristan Stubbs had yet to face a delivery when Marco Jansen took guard.

Much has been made of the depth of the South Africans' batting. But that doesn't count for much when your batters keep getting themselves out. Markram didn't. The rest of the top five did.

Stubbs and Jansen changed that narrative with a partnership of 73 off 48 that Ferguson ended in the 19th with a leg cutter that nailed the swiping Stubbs' off stump. At 150/6 the South Africans at least had earned themselves something to bowl at.

How many more would they get from the 11 balls that remained in their innings? Nineteen, not least because of Jansen's swing low sweet chariot approach that saw him lash two fours and five sixes in his unbeaten 55. There might have been more, but Jansen faced just two deliveries in a last over in which Henry removed Corbin Bosch and Kagiso Rabada with consecutive balls.

Would 169/8 be enough to hold the New Zealanders? South Africa had won after scoring fewer batting first, but was against a Zimbabwe side who had been run ragged in their first two Super Eights matches and were wondering how they were going to get home with war raging in the Middle East.

The pitch slowed the ball's progress onto the bat, and South Africa's bowlers were better than New Zealand's. But, to conjure a contest with comparatively few runs to play with, the Kiwis would likely have to bat as poorly as their opponents.

The issue was settled after the Powerplay. South Africa were 48/2 after theirs. New Zealand roared to 84 without loss, or one less than half the target. Tim Seifert hit 11 off Jansen's first over, albeit edgily, and he and Allen took eight off Rabada's opening effort. Then Jansen flew for 18, Lungi Ngidi for 11, Rabada for 14, and Bosch for 22.

It took New Zealand another 6.5 overs to seal a comprehensive victory - by nine wickets, with 43 balls still in the bank - that everyone present knew was on its way. Seifert and Allen put on 117 off 55, and Allen and Ravindra knocked off the remaining 53 off 20. Allen's 100 not out boomed off 33 hapless deliveries, 10 of them hit for four and eight for six.

The crowd was speckled with lit phones as Jansen steamed towards Allen with the scores tied and him four short of his third T20I ton. The ball arrived fullish and eminently hittable. Allen did exactly that, hammering a boundary through long-off to seal the deal.

As they shambled off the field, the South Africans might have asked themselves who that was out there in the yellow shirts and green trousers. Whoever they were, they weren't the team who had reeled off seven wins without reply. They had failed to turn up, and now they are on the long way home.