Grant Elliott played a match-winning knock of 84 to carry New Zealand through to the final of the ICC Cricket World Cup.
The Black Caps won a four wicket duckworth/lewis victory over South Africa in dramatic circumstances, with Elliott striking the decisive six off the penultimate delivery of the match.
Captain Brendon McCullum got his side's pursuit of 298 for victory, in 43 overs, off to an explosive start by scoring 59 off 23 balls at the top of the order.
Morne Morkel's three-wicket haul brought the Proteas back into contention and the Kiwis needed 12 to win off the final over.
Daniel Vettori, who finished seven not out, squeezed a crucial boundary through the off-side before scampering a bye to leave Elliott on strike with five needed to win off two deliveries.
Elliott pulled Steyn over the midwicket fence for a maximum to win it with a delivery to spare, sending the Eden Park crowd into rapturous celebrations.
South Africa won the toss and elected to field at Eden Park before a brace of wickets from Trent Boult had them in early trouble at 31-2.
The Kiwi left-armer dismissed Hashim Amla for ten and Quinton de Kock for 14 to overtake Geoff Allott's record haul of 20 wickets by a New Zealander at the 1999 World Cup.
But with Francois du Plessis scoring 82 off 107 balls to provide the backbone, South Africa's middle-order was able to accelerate either side of a lengthy rain interruption which shortened the contest to 43 overs-per-side.
Rilee Rossouw scored 39 off 53 balls in an 83-run third wicket stand alongside the former Lancashire man, setting the platform for Ab de Villiers and David Miller to cut loose late on.
The South African Captain finished 65 not out off 45 deliveries with eight fours and a six.
David Miller hit three maximums and six fours in his 18 ball cameo of 49 as the pair added 55 runs in four overs, taking the total to 281 and activating a recalculated duckworth/lewis target of 298.
McCullum came out all guns blazing, bringing up he New Zealand fifty by planting Dale Steyn 20 rows back over long-on off the first ball of the fifth over.
Two balls later, the New Zealand Captain had reached his own half-century off 22 balls, with six fours and four sixes.
Typically he reached the landmark by pulling Steyn for a maximum, before celebrating with further back-to-back boundaries as the Black Caps reached 71-0 after five overs.
A maiden introductory over form Imran Tahir started to change the emphasis as Martin Guptill struggled to get the leg-spinner away.
McCullum was out, caught at mid-on off Morne Morkel, off the first ball of the following over. He scored 59 off 26 balls.
The Proteas were right back in the contest when Kane Williamson played-on to a short pitched delivery from Morkel with only ten further runs added to the total.
But a stand of 47 between Guptill and Ross Taylor ensured there was no cluster of wickets. And, although Guptill was run out for 34 and Taylor caught behind off JP Duminy for 30, the Kiwis were 149-4, after 21.4 overs, when Elliott and Corey Anderson came together.
A crucial stand of 106, in 16.2 overs, put the Black Caps in a positions of control with Anderson the first to pass 50, his second of the tournament, off 47 deliveries.
Elliott reached the landmark soon afterwards, in 53 balls, and - although du Plessis took a skier to dismiss Anderson off Morkel with 46 still needed from five overs - the New Zealand number six continued to guide his side towards victory.
Luke Ronchi was caught on the leg-side boundary, off Steyn, bringing Daniel Vettori to the crease - and New Zealand needed 12 to win off the final over.
Steyn appeared to be suffering with cramp and Elliott, who faced 73 balls with seven fours and three sixes in all, took full and decisive advantage.
View the full match scorecard here
Trent Bridge hosts the fourth Royal London One-Day International between England and New Zealand on Wednesday 17 June. Don't miss the chance to watch England seek redemption against the Kiwis and secure your seat now.