Shakib Al Hasan shone with bat and ball to help Bangladesh to a morale-boosting win in the team's first meeting overnight (NZtime).
He hit 58 off 51 to steer the hosts to a competitive 228 all out and then grabbed four wickets to restrict New Zealand to 200 for eight at the Sher-e-Bangla National Stadium on the outskirts of Dhaka.
Bangladesh won by nine runs through the Duckworth-Lewis method after rain midway through the second session forced the Black Caps' target to be revised to 210 in 37 overs.
It was only the second win for Bangladesh in 18 one-dayers against New Zealand and gave them the early advantage in the five-match series.
"Any loss is disappointing," Vettori said in a post-match interview.
"We put our self in some good positions and we should have chased down that score. Unfortunately we just lost too many wickets at crucial times and that was the reason we lost today.
"The Duckworth Lewis didn't help us. To lose 13 overs, all our power play overs and only reduce the score by 19 runs doesn't seem quite right but it is what it is and we still should have chased down that total.
"He (Shakib) played really well, he was the difference between two sides. His batting gave Bangladesh a bit of impetus going into the end and then he is always a danger with the ball.
"He is the guy we will have to nullify a little bit if we want to win the next four games."
Shakib, who stood down as captain to concentrate on his cricket, hit eight fours after skipper Mashrafe Mortaza won the toss and elected to bat first.
Recalled opener Shahriar Nafees made 35 and Junaid Siddique chipped in with 30, but the Bangladeshi batsmen failed to build on good starts.
Vettori led from the front with 2-29 in 10 overs of accurate left-arm spin, while seamer Kyle Mills grabbed three wickets for 44 runs.
Jesse Ryder and Andy McKay took two wickets each.
Brendon McCullum gave the Kiwis a rousing start with 61 off 45 balls, including seven fours and two sixes.
McCullum and Jesse Ryder put on 53 for the first wicket by the seventh over, before three quick wickets from Shakib reduced the tourists to 85-4 by the 15th.
Heavy rain at that stage toughened New Zealand's target, but Ross Taylor battled bravely to make 42, while Vettori contributed 24.
"We had a reasonable start and to restrict them to less than 230 was a good effort," Vettori said.
"We expected to win, but we let ourselves down in the second half of our batting effort.
"Brendon played really well, he gave us impetus but we couldn't back him up."
"We have got to get back on track for the next game, and it is all about the next game so we are looking forward to that one."
