Age isn't just a number in New Zealand cricket. Instead, it's a good thing. As in, the higher the better. Eleven members of their men's T20 World Cup squad of 14 are 30 or older, and five of those are at least 34. South Africa, their opponents at Narendra Modi Stadium on Saturday, have six under-30s in their 15.

Kwena Maphaka, a tender 19, is the youngest member of both squads. But, age being the complicated curmudgeon it is, it shouldn't surprise us that the oldest player is also South African: uncle David Miller is 36. The average of Saturday's XIs? New Zealand's was 31.27, South Africa's 29.64.

That didn't raise Rob Walter's eyebrows: "The average age of the New Zealand side is always high. The guys play a lot of domestic cricket before they eventually push through. While there isn't a huge amount of cricketers, they've got a strong team. And with a strong team you have to play really well to get in. But they also give their cricketers time. At domestic level, if you haven't dominated by the time you're 22, you're not pushed away for the next 18-year-old.

"They understand that the game is hard and you don't just become good at it quickly. Sometimes guys only make their debuts at 30 and 31. And we're not scared of that. We're OK with guys playing their best cricket at 36. We're not looking for someone to replace them. That's a major strength.

"You'll have generational talents who come through younger - [Tim] Southee, [Trent] Boult, [Kane] Williamson, and that's fine. But, for the most part the world over, those guys who tend to come in as young prodigies have to knock their heads a couple of times, lose form, get dropped, and then come in and be better. New Zealand has traditionally done it in reverse and allowed that to happen at domestic level.

"There are a couple of things that happen [below international level] that create the depth and the strength. New Zealand are proud of the fact that they use what they have to do what they do. They're not entitled and they don't have a lot of money, so they don't walk around as if they do. They make it work."

Did it work on Saturday? New Zealand's 175/7 - the lowest first innings at this ground in the three games in the tournament so far - after being put in to bat on the same red-soil pitch that staged the double super over spectacular between South Africa and Afghanistan on Wednesday never looked like enough. Mark Chapman and Daryl Mitchell shared 74 off 44, but no other stand reached 35. Marco Jansen deployed his bouncer, slower ball and knuckler to devastating effect to take 3/30 in his first three overs.

Then Aiden Markram set about winning the game with a blistering blast of 86 not out off 44. Markram hit the ball mostly straight or in the V, and so hard that a smidgen less than two-thirds of his runs came in fours and sixes. South Africa's 83/1 after six equalled the highest number of runs they have scored in a T20I powerplay. It was also 25 more than the Kiwis made. Midway through their allotted overs, South Africa were 119/2 - just 57 away from winning and 27 runs and two wickets betters off than their opponents at the same stage of their innings.

They won by seven wickets with 17 balls to spare, and looked like a team who were playing their third game of the tournament at the world's biggest cricket ground - where 54,293 turned up on Saturday. The New Zealanders looked unsettled. They were in Chennai for their first two games, and they will go back there to play Canada on Tuesday.

Chapman is 31, Mitchell is 34, Jansen is 25, Markram is 31. Where does that leave the agonising over age? Undecided, of course. Because, as Charlotte Bronte wrote in Jane Eyre, "... your claim to superiority depends on the use you have made of your time and experience".

It's worth remembering that Leonardo da Vinci started painting the Mona Lisa when he was around 51 and didn't complete it until he was in his 60s. "The Cat in the Hat" was first published when Dr Seuss was 53. Not least because he spent 27 years in various apartheid prisons, Nelson Mandela was 75 before he was inaugurated as South Africa's first properly elected president.

Mention of apartheid leads us to CSA's attempts to redress the sins of the past by skewing selection in favour of black and brown players. Walter was South Africa's white-ball coach from January 2023 to April 2025. His appointment as New Zealand's all-format coach was announced in June last year. It must be easier to pick squads and teams without having to tally the race numbers?

"You're always just trying to do the right thing," Walter waxed diplomatically. "Different factors influence selection when you're sitting in different changerooms. There's always something to consider. From that point of view, I have just as many sleepless nights now. You're always trying to pick the best team and do the right things for the team that you coach.

"Resources look different. Teams have different strengths in different areas. If you had to pick any team around the world, there's certain guys who pick themselves. They're the first names on the list. And then you're trying to balance the team, whether that's strength balance or skills balance or conditions balance. So you have different considerations. It's just that the parameters have changed."

Still, South Africans of a reactionary bent were quick to theorise that Walter left with two years remaining on his contract because of political problems. Was that true?

"You can discuss many sides of the coin in terms of the timing and the reasons," Walter said. "But for me it felt like it was the right time to move on."

The fact that the South Africa role was split between him and red-ball coach Shukri Conrad seems to have played a role, as Walter explained: "It's complicated when there's two different voices from the head coach. Myself and Shuks spoke regularly, so it's not like there was friction. I think we got on great. But you do still have two different head coaches."

As a measure of his support for Conrad's team, Walter cited his reaction to South Africa beating Australia in the WTC final at Lord's last June: "I'm super chuffed that South Africa achieved that success. Everyone involved in [South African cricket] can celebrate that moment."

Besides, "It was not about why Rob Walter left. It was because it would be unfair to the system to talk about that. Obviously I have my own reasons. Some were related to the job. Others were related to family. But that's almost irrelevant. What's relevant is South African cricket has gotten stronger. They've gone on to achieve great things. That's the most important thing for South Africa to focus on."

Their focus was unshakeable on Saturday. They aren't yet guaranteed a place in the Super Eights, but it is difficult to imagine the United Arab Emirates denying them that achievement in Delhi on Wednesday.