The Volts clawed their way to 269 for nine.
The tally looked a little lean, but Michael Rae nabbed four for 39 in an energetic spell, and Jacob Duffy picked up three wickets at the death to help dismiss Canterbury for 232.
Michael Rippon played a key role with the bat at No 5.
He added 77, and opener Nick Kelly found some form with a valuable knock of 76.
The win has lifted Otago to four wins from eight games.
Wellington and Auckland also have four wins, while Northern Districts and Canterbury have five wins apiece.
Central Districts has slipped out of contention with one win from seven completed games.
Hamish Rutherford's lean run for Otago continued.
Ed Nuttall got a bumper to lift sharply and take the edge of his bat.
Rutherford scored just one run from 15 balls, and looked out of touch.
Kelly has been searching for form as well. But the left-hander anchored the innings, and Rippon justified his promotion up the order with a mature innings.
Rippon took a while to get going, but chipped in with some handy boundaries late.
He swatted a couple of sixes in the last over before holing out from the last ball.
Matt Henry was the best of the Canterbury bowlers. He picked up the key wicket of Kelly and finished with three for 37.
Canterbury muscled its way into a strong position at 140 for three.
Rae had grabbed a couple of wickets, including the important scalp of Henry Nicholls.
With the game drifting away, Rae returned to the bowling crease.
The Volts needed their energiser to batter down the defence.
Cole McConchie helped out. On 45 he drove the ball to Nathan Smith.
That little opening expanded when Tom Latham edged Rae through to the keeper for 36.
By the time Todd Astle (6) had swatted a short ball from Mitchell McClenaghan to a fielder, all the pressure swung to the visitors.
Sean Davey swatted 43 but Duffy took three wickets in the 49th over to seal the win.
In the other games, Auckland crushed Central Districts by 93-runs at Eden Park Outer Oval.
Opener Cole Briggs slapped 99 to help the Aces post a challenging total of 311 for nine. The rookie scored a hundred on debut on Friday, so he is one to watch.
The Stags could only manage 218 in reply. It was a milestone day for Ross Taylor, who joined the small club of New Zealanders to have played 300 List A one day games, but he could only manage 9 at the crease.
At the Basin Reserve, Wellington defended its modest tally of 188 against Northern Districts.
