South Africa remain the tournament's only unbeaten team and their seven wins in a row include a seven-wicket thumping of New Zealand in the group stage in Ahmedabad.
But neither side are reading too much into that result with Proteas captain Aiden Markram insisting they will take nothing for granted on Wednesday (Thursday 0030 AEST).
"I wish cricket was that easy," Markram said. "New Zealand are a quality team, they've proved that over many years now.
"We had a good run-out against them in the group stage. But both teams have played a lot of cricket since then, and it's completely a fresh start tomorrow. I don't think it's as straightforward as just being able to repeat that again."
"We haven't probably played the perfect game throughout this tournament. I guess that's a good thing for us," Santner said. "If we can put it all together it puts us in a pretty good position.
"We know South Africa are going to be a threat. We're just going to try to put some pressure on them at different stages of the game, and they're going to do the same for us."
Neither team has previously played in Kolkata this tournament and both captains said much will depend on the conditions and who adapts to them best.
Markram said South Africa's perfect run was down to their smart cricket, highlighting the calm decision-making coursing through the group and the influence of wicketkeeper-batter Quinton de Kock.
"I think it's more just around making really good decisions under pressure. We've got a lot of good experience in the group.
"Quinny reads conditions really well from behind the stumps, and that makes a massive difference for us. We get that around the group, and the guys come up with plans from there. Ultimately, you need to execute them. We don't try to complicate too much."
Both teams are chasing a first men's white-ball World Cup triumph having each lost in recent T20 finals, New Zealand in 2021 and South Africa last time out in 2024.
New Zealand also lost the 2015 and 2019 50-over World Cup finals
The Black Caps' Matt Henry, who had returned home on paternity leave, will rejoin the squad on Tuesday night and Santner could not confirm if he would play.
