Finn Allen opens the over with a six down the ground off Marco Jansen - the first off the New Zealand innings.

Two balls later, Quinton de Kock thinks Tim Seifert has nicked one and Aiden Markram decides to review.

Finn Allen is well and truly off the mark with a boundary down to third.

And New Zealand are 19 without loss after two overs.

Steven Finn
Former England fast bowler on BBC Radio 5 Sports Extra

The fine-leg fielder should have gone for that rather than the keeper trying to get it over his shoulder.

Dropped catch - Siefert on 11published at 1.2 overs

1.2 overs

NZ 12-0 | Target 170

This has gone up a mile in the air after a top edge from Tim Seifert.

Wicketkeeper Quinton de Kock calls for the catch but has to make plenty of ground to get to it but can't take it!

New Zealand survive another early scare. Is this their night?

Steven Finn
Former England fast bowler on BBC Radio 5 Sports Extra

Rabada is one of my favourite bowlers to watch but has only got four wickets in this tournament. Now would be a great time to come to the party.

Kagiso Rabada has the ball from the other end.

New Zealand captain Mitch Santer has opted for a slip for the pacer.

Steven Finn
Former England fast bowler on BBC Radio 5 Sports Extra

Image source, Getty Images

It's actually well bowled, Jansen is unlucky not to get the breakthrough in that over.

There’s some lovely in‑swing straightaway from Marco Jansen, but Tim Seifert reads it early and drives his second delivery through point for four.

Jansen responds with a pair of edges - the first flying past the wicketkeeper for another boundary and the next dropping just short of short third.

New Zealand won’t mind any of that. It’s a brisk start for them.

Steven Finn
Former England fast bowler on BBC Radio 5 Sports Extra

The last seven or eight overs of the South Africa innings suggested the ball is skidding on a bit now.

After his heroics with the bat, Marco Jansen has had little time to rest.

He now has the ball in his hand to launch South Africa's bowling attack.

And his first delivery is well defended by New Zealand opener Tim Seifert.

Tim Seifert and Finn Allen stride out to open the batting for New Zealand in Kolkata.

They'll know they need a rapid start against this South Africa bowling attack to set the tone for the chase.

It's time to find out who among these two sides will book their place in Sunday's final.

Image source, Getty Images

New Zealand bowler Cole McConchie: "We talked about [him] taking the new ball after the warm-up. It was nice to come in and contribute."

On the wicket: "It was about going hard to get something early and the way that the South Africa lads batted at the end, makes it look like the wicket got flatter. Hopefully it will be a good chase."

On the team: "There are a few nerves with the semi-final but it is nice to come in and take some wickets. We would have taken this at the start of the game but we need to be on top in the chase."

But Marco Jansen's unbeaten 55 from 30 balls and a 24-ball 29 from Tristan Stubbs have guided South Africa to a decent total here.

It still feels like very chaseable for New Zealand but it’s a T20 World Cup semi‑final - pressure can tell and the momentum swings are rapid.

Let’s see how the Black Caps respond during their chase.

Thanks, Elizabeth.

New Zealand captain Mitch Santner talked about the need for making "inroads at the start" after putting South Africa into bat first at the Eden Gardens.

And that's exactly what he got from his off-spinner Cole McConchie, who gave the Black Caps a brilliant start with two wickets in the second over.

From 12-2 in the powerplay, 77-5 following the wicket of Dewald Brevis in the 11th over, and 108-5 heading into the final five overs, South Africa should be pretty content with 169-8.

Some crucial late hitting from Marco Jansen but will it be enough?

Here's Adwaidh Rajan to take you through New Zealand's chase.

It's full from Matt Henry and Marco Jansen can't get it away. He comes back for the second run and just beats the throw into the wicketkeeper.

South Africa finish on 169-8, with Jansen unbeaten on 55 (30).

New Zealand need 170 to reach the T20 World Cup final.

Sensible stuff from Keshav Maharaj, dabbing for a single. What can Marco Jansen do with the final ball?

Dawid Malan
Former England batter on BBC Radio 5 Sports Extra

You have to question Kagiso Rabada there. Your job is just to get someone on strike!

Two balls can cost you 12 runs in this contest - it is a silly decision.

Simon Mann
BBC Test Match Special commentator

That was not the best shot from Kagiso Rabada. New Zealand will be really happy with this.