Brad Haddin's second one-day international century gave Australia a 2-1 lead and the most one-sided victory of the tour, as they chased down their target with 16 balls to spare.
Haddin's 110 was his highest ODI score and he ended Daniel Vettori's hopes of winning what he said before the match was "the most important game of the series".
Ricky Ponting was annoyed in the opening two games at his batsmen's inability to capitalise on their starts, and they resolved that problem at Seddon Park. Ponting made 69 and combined with Haddin for a matchwinning 151-run partnership that justified Ponting's rare decision to send New Zealand in. It is a gamble he has taken 24 times in his ODI captaincy career for a remarkable 20 victories.
His bowlers did the job early by dismissing New Zealand for a thoroughly gettable 245 and in the chase, Haddin set about determining the result early. Haddin loves batting against New Zealand; his only two ODI hundreds and his first Test century have come against them, and in all three forms of the game he averages 52.06 against New Zealand compared to an overall career mark of 34.55.
He did cruel things to Michael Mason, who at 35 was playing his first international since mid-2008 and must have finished the day wondering if fighting back into the team was all worthwhile. Mason's opening delivery, a no-ball, was dabbed by Haddin for four past the wicketkeeper and the subsequent free-hit was slapped contemptuously back over his head for six.
It left Mason with the extraordinary economy rate of 66 after one legal delivery. Haddin drove two more boundaries in the over, which cost Mason 20, and the bowler was lucky that his ten overs cost only 68. Haddin brought up his fifty from 51 deliveries and also attacked with confidence against Scott Styris, who was hit back over his head for six.
Haddin's timing was exquisite and his shots appeared effortless. Every one of his seven fours and five sixes was felt by Shane Bond, who had put down an extremely tough caught-and-bowled chance when Haddin was on 8, and later by Tim Southee, who put him down on the boundary when he had 83. He ended up being stumped advancing to Vettori with 16 runs still required, and Cameron White and Adam Voges finished the job at a reduced pace.
It was the Haddin-Ponting partnership that buried New Zealand. Ponting's half-century came at nearly a run a ball and featured seven boundaries but it was a support role. The best bowlers, Vettori and Bond, were respected while Styris and Mason were targeted by the two Australians. They knew that Vettori's bowling options were limited and the only wicket in the first 30 overs was the run-out of Shane Watson for 15.
All in all, it vindicated Ponting's unexpected decision at the toss; Vettori said he would have batted if given the choice. There was little assistance for Australia's bowlers on a good batting surface but after a footwork-free Peter Ingram edged Ryan Harris behind in the first over, New Zealand struggled to make the best of the opportunity and slipped to 55 for 3.
They had much the same problem Australia had endured in the first two games when they batted first: batsmen falling after making promising starts. Five of New Zealand's top six made scores in the 20s to 40s and Ross Taylor was the only man who went on and registered a half-century, although even his 62 was short of what it could have been.
Having missed the Auckland loss due to a leg injury, Taylor showed the rest had not done him any harm as he rocketed off the mark with a crunching square-driven boundary off Mitchell Johnson. He struck a pair of sixes, one pulled off James Hopes and one slog-swept off Nathan Hauritz, and moved to his half-century from 45 balls.
But the Australians knew that if they could tie Taylor down they might get a chance, and it came when he faced 20 balls without a boundary just after passing fifty. Watson came on and sent down a bouncer, Taylor's eyes lit up and he went for the hook, the ball skied off the top edge and Michael Hussey completed the catch at deep square leg.
It was a crucial wicket and left New Zealand five down in the 30th over. Styris continued his consistent series with 41 and combined with Gareth Hopkins for a 67-run stand that pushed the hosts past 200 but when they departed, so did New Zealand's hopes of batting out their overs.
Styris skied Watson to long-off and Hopkins, who improvised well in his career-best 45, was taken at mid-off from the bowling of Harris, who finished with 3 for 48. Johnson grabbed three wickets as well and the final three New Zealanders fell for five runs and they were bowled out with 22 deliveries still available.
Of course, it was the top-order men who should have stayed at the crease longer. Brendon McCullum (23), Martin Guptill (21) and Neil Broom, who laboured to 24, missed their chances against a ball that wasn't really swinging. Australia fixed their similar problem in this match; New Zealand must do the same on Thursday to stay in the series.
