The Otago middle-order batter anchored the Volts' chase yesterday with an undefeated knock of 72 from 74 balls.
Canterbury lost early wickets but recovered somewhat to post a modest tally of 222.
Otago overhauled the target with five wickets in hand and more than seven overs spare.
While it was not a daunting target, teams have tripped up chasing smaller totals and Canterbury had a window of opportunity when Neil Broom nearly holed out.
But Finnie took control with a commanding performance.
The right-hander is better known for his hitting power and innovation. Those skills have mostly been deployed at the end of the innings.
But the 24-year-old is trying a few different roles this season.
He is making the most of those natural talents and opening the batting in the Super Smash.
The part-time off-spinner has also got the ball in his hands a lot more.
Finnie has also slotted in at No5 in the one-day order and with it comes added responsibility.
That responsibility sat well with him yesterday.
He combined with Broom to add 95 from 89 deliveries for the fourth wicket.
"I had a chat with Dion [Ebrahim, Otago coach] in the winter about how I like to play and [opening in T20] just gives me the ultimate freedom to go out there and play the way I like to play without worrying too much [about the equation]," Finnie said.
"It is where I want to make my mark and hopefully things go well out there."
Finnie has more than the one gear, though. When Broom was dismissed for 50 and Kitchen went cheaply, he scaled back his ambition and looked to nudge Otago to victory.
It was a controlled innings from a player who has typically followed his instincts.
If he could bowl a few overs, it helped with the mix of the side, he said.
Earlier, Canterbury made a late charge towards a respectable total.
The visitors had slumped to 90 for six before Henry Shipley (55) and Theo van Woerkom (41) staged a revival.
They both posted career-high list A scores and shared in a 96-run record seventh-wicket stand for Canterbury against Otago.
The Volts' bowling unit dominated the opening exchanges.
Opener Jack Boyle chased width but only got an edge. Ken McClure gloved a hook shot and Chad Bowes nicked a drive.
That was the top three done with just 50 on the board. Kitchen saw off the next three.
The left-arm spinner bowled Canterbury captain Cole McConchie.
Cam Fletcher swiped a full toss straight to Broom at square leg.
And Leo Carter duffed a lofted drive and was caught in an excellent diving catch by Michael Rippon.
A late flurry of wickets saw Matt Bacon finish with four for 45. Kitchen's three for 36 was tremendous value and Duffy also bowled a top spell.
Otago's chase got off to a bright start with Hamish Rutherford (24) dispatching some sumptuous drives.
Canterbury missed a big opportunity to wrestle back momentum when Ed Nuttall dropped Broom on 22.
The Volts had just lost Phillips (43) and Nick Kelly (1) in close succession.
Another wicket there and, well, who knows.
Rutherford and Broom are just so crucial but Finnie had it under control and paced his innings nicely.
The Volts' next assignment is a T20 against the Central Stags in Napier on Saturday.
