Bangladesh were all out for 93 in the 38th over, with Vettori returning a magnificent five for seven, and then McCullum blasting the Bangladesh bowlers out of the park as New Zealand reached their target in just six overs.
The astounding performance, where the match was over before the scheduled first innings break, sealed a 3-0 series clean sweep for New Zealand.
McCullum’s unbeaten 80 came off 28 balls and included a contemptuous nine fours and six sixes.
Along the way he posted the fastest ODI half-century by a New Zealander, from 19 balls, and he missed equalling the world record by three deliveries. At the other end, Jamie How was a virtual spectator, contributing only seven of the 95 runs scored.
Vettori overtook Chris Harris as New Zealand’s leading ODI wicket-taker, ending the innings with a 207 total, four ahead of his former teammate. Vettori will also end 2007 as cricket’s most successful bowler for the calendar year with 43 victims, three clear of Indian paceman Zaheer Khan.
For Bangladesh, captain Mohammad Ashraful once again top-scored with 25 before being undone by his favourite pullshot when he delivered the ball straight into the hands of Jacob Oram at fine leg. Vettori took Aftab Ahmed and Shakib Al Hasan in one over and followed with the wickets of Farhad Reza and Mushfiqur Rahim in his next two overs before clean bowling Mashrafe Mortaza.