Andrew Fidel Fernando is ESPNcricinfo's Sri Lanka correspondent. @afidelf
New Zealand 319 for 7 (Taylor 90, Munro 87, Neesham 64, Malinga 2-45) beat Sri Lanka 298 (Thisara 140, Gunathilaka 71, Sodhi 3-55) by 21 runs
A spectacular Thisara Perera power-hitting showcase was not enough to lift Sri Lanka out of a pit of the middle-order's making, though it did fill the chase of 320 with much more explosive fun than it promised when Sri Lanka were 128 for 7. Thisara wallopped 13 sixes and eight fours on his way to 140 off 74 balls - each of New Zealand's death bowlers given a painful shellacking.
But with 22 still needed for victory, and only No. 11 Nuwan Pradeep for company, Thisara mis-hit a length ball from Matt Henry towards long-on, from where Trent Boult sprinted forward to complete an excellent diving catch.
That New Zealand even found themselves in this situation, after having had the opposition virtually toppled in the middle overs, was down to uncharacteristically poor catching earlier in the night. No fewer than five clear-cut chances went down, including off Thisara when he had been on 79 - Kane Williamson the culprit on that occasion, letting a the ball slip through his fingers at long-off.
In the end though, their dramatic middle-overs collapse, in which Sri Lanka had lost five wickets for 16 runs, proved to be the definitive period of the game. Thisara's heroics, at least, were further evidence that he is a vastly improved batsman in the past 12 months. His century off 57 balls was the fastest against New Zealand. Only five batsmen have hit more sixes in an innings - his 13 beating the Sri Lanka record of 11, which had been held by Sanath Jayasuriya since 1996.
So breathless were the final 40 minutes of the game - Thisara's blows raining down on Bay Oval like a meteor shower - that the New Zealand performances that set up this series-clinching victory seemed a distant memory by the end. Those efforts, however, were nevertheless outstanding. Colin Munro struck a 77-ball 87, putting on a 112-run stand for the third wicket with Ross Taylor that formed the base for New Zealand's commanding total. Taylor himself continued his sublime ODI form, hitting 90 to make it five successive fifty-plus scores in the format, and eight fifty-plus scores in the last 10 innings.
James Neesham provided another round of death-overs fireworks, clobbering 64 off 37, before proving effective in the middle overs once more. And legspinner Ish Sodhi was terrific on what was now a surface offering moderate turn, taking 3 for 55 from his 10 overs, having precipitated that Sri Lanka middle-order meltdown.
The Sri Lanka nosedive was swift and in many ways predictable. Whenever the top order has bestowed a half-decent foundation, in recent months, the middle order has almost uniformly tended to crumble under the pressure of keeping the momentum going. This time, Sri Lanka were 112 for 2 after 22 overs, thanks largely to a half-century from opener Danushka Gunathilaka, before they virtually surrendered the match.
Kusal Mendis was the first to fall, for 20 off 30 balls, edging the ball as he attempted to sweep Sodhi - wicketkeeper Tim Seifert moving expertly down the leg side to complete a tough catch. Gunathilaka was out next over, attempting to lift James Neesham over wide mid-on, and managing only to send a high catch off the top edge, also to be snaffled by Seifert. Dinesh Chandimal was out next, completely failing to read a Sodhi googly, which leapt back into his stumps as he was shaping for the cut, before Asela Gunaratne ran himself out calling Thisara through for a suicidal single. The last wicket in this period was the result of another Sodhi googly - Seekkuge Prasanna playing all around it as he tried to hit the bowler into the stratosphere.
By now Sri Lanka's plight seemed desperate, but Thisara warmed to his work with a spate of fours, before the first six came, off Tim Southee, who bowled a waist-high short ball which was bludgeoned over deep square leg. Soon, the big blows came like an avalanche. There were two Thisara sixes and a four off Sodhi's final over - the 33rd of the innings - and another four off Matt Henry, before his partner Lasith Malinga - who had been dropped twice - was finally out, bowled off his pads by Trent Boult, for 17. That partnership had been worth 75 off 50 balls.
The next stand brought another 51, to which Lakshan Sandakan contributed only six runs. The rest were all Thisara thrashings. Although towards the start of his innings, Thisara played regularly through the offside, he was bashing balls through his main hitting zone - the arc between wide long off and midwicket - by the end of it. He raced past his previous best score of 80, brought up his ton with a single in the company of Sandakan, and once the ninth wicket had fallen, produced his most brutal hitting for the last-gasp lunge toward victory.
After having been earlier belted around by Neesham for the second time in as many games, Thisara launched him for two sixes in the 45th over. Then, with 50 required off 30 balls, he clubbed four sixes off Tim Southee to bring the equation down to almost a run-a-ball. Although the Henry ball that undid him was in the slot, Perera could not quite bully it over the rope as he had done previously - perhaps some fatigue having weakened his muscles.
Earlier in the day, Taylor had played New Zealand's best innings, though Munro had provided the early fireworks. Taylor's was a characteristically wise knock from a batsman at the top of his game. He was measured through most of the innings, only occasionally venturing a big shot, and instead manipulating the ball into gaps efficiently. Only 22 of his runs came from boundaries, with singles and twos on the leg side most heavily populating his innings. He might have got to triple figures himself, had he not unselfishly looked for two after turning a ball to square leg - the return throw from Kusal Perera catching Taylor just short of his ground.
Sri Lanka effected four run outs in the innings, but even that didn't quite make up for their lack of menace in the middle overs again.