New Zealand maintained their perfect World Cup record as they beat co-hosts Australia by one wicket in an incredible game at Eden Park.
Chasing just 152 having run through the Aussies inside 33 overs, New Zealand slipped from 131-4 to 146-9 before Kane Williamson ended the contest by lofting Pat Cummins for six over long-on.
It was an appropriate end to a Pool A contest of relentless drama in which Trent Boult (5-27) and Mitchell Starc (6-28) both finished with career-best figures and Brendon McCullum (50) smashed his latest half-century from 24 balls.
And victory leaves New Zealand - now with four wins from four games - well-placed to finish top of the group with just Bangladesh of the Test-playing nations still to play.
Australia, batting first on their returning captain Michael Clarke's call, took Tim Southee's first over for 15 and progressed serenely enough to 80-1 before the mayhem began.
Daniel Vettori induced a rash Shane Watson shot and had Steve Smith caught at the wicket either side of David Warner's dismissal, trapped in front by Southee and unreprieved by a review.
The real chaos was still to come, though, left-armer Boult collecting the next five wickets as the Aussies slipped from 96-4 to 106-9 in the space of 28 balls.
Clarke - playing his first one-day international since November - was among those to fall to Boult, whose figures represented his first five-wicket haul in ODI cricket.
Brad Haddin hit out for 43 to get Australia to 151 - their lowest World Cup score batting first - but even that looked indefensible as McCullum and Martin Guptill both belted their second balls faced for six.
McCullum added two more maximums before he was second man out with the score on 78, and Starc then splayed the stumps of Ross Taylor and Grant Elliott with sucessive deliveries to leave the Kiwis 79-4.
A fifty stand between Williamson and Corey Anderson restored order, but the latter's reckless swipe at Glenn Maxwell precipitated the loss of five wickets in 21 runs as Starc re-entered the picture.
Again Australia's left-armer left himself on a hat-trick, this time Adam Milne and Southee the men clean bowled, and this time one more wicket would have brought victory for his side.
But Boult blocked his first ball and left his second to see out Starc's over, and Williamson (45 not out) finished the job with one blow.
Watch highlights of New Zealand's dramatic win over Australia on Sky Sports World Cup at 3pm, 5pm and 7pm.