They lost five wickets in the last five overs to almost squander a comfortable lead in the Super Smash game.
It was left to spinner Eden Carson to chip the ball over midwicket to clinch the win from the last ball of the game.
The Sparks produced a disciplined bowling effort to restrict the home team to 109/6.
Otago openers Suzie Bates (23) and Bella James (26) put on 53 for the first wicket, and Olivia Gain (18) and Felicity Robertson (15) added 32 for the third wicket.
The Sparks should have been able to coast to victory from there but the chase unravelled.
They found the panic button and pushed it repeatedly instead.
Canterbury did defend nicely, though. They fielded well and kept fighting.
But the Sparks laid the platform for the win with the ball.
Emma Black led the charge.
She bowled three of her four inside the powerplay.
The right-armer got her inswinger going nicely and, while she went wicketless initially, she also only conceded 11 runs in her first three.
Canterbury opener Kate Anderson offered a half chance early.
She thumped back a drive to the bowler Hayley Jensen, who avoided injury but couldnot stick the catch.
The Sparks had built up some pressure and that paid off for wrist spinner Sophie Oldershaw.
She trapped Anderson lbw for 24.
There was hint the ball might have spun past leg stump but the umpire saw it differently.
Fellow opener Frankie Mackay (20) tried to break the shackles with a shot over the top but skied a catch to Carson.
Impressive left-armer PJ Watkins picked up the wicket.
She nabbed four on debut before Christmas and grabbed another two scalps in this game.
Izzy Sharp was dropped on 16.
She lobbed the ball to long-on, but Gain made a critical error.
She miscalculated and came in a metre or two and the ball sailed over her head.
That was the first of three missed opportunities to remove the right-hander.
She eventually went for a game-high 32.
Canterbury promoted Lea Tahuhu to club some quick runs off the last three overs.
But they had let too many overs slip away without forcing the rate.
Natalie Cox was robbed of a six late when Robertson stuck out a right arm and pluck the ball out of the air at full stretch.
Cracking catch that one.
But it was a mixed effort in the field by the Sparks.
Carson dropped a sitter last ball.
Canterbury needed early wickets and, in particular, the wicket of Bates.
But the Otago captain stroked a lovely drive down the ground to get her innings under way.
She also pulled a shorter delivery through midwicket for another boundary.
James did not get a lot of the early strike, but she played a lovely pull shot for four and also dispatched Tahuhu over her head for four.
Canterbury only managed seven boundaries in total, whereas Otago had collected five inside the powerplay.
They desperately needed a breakthrough or two and they got them.
Bates got trapped in front by Sarah Asmussen trying to sweep the ball, and James was run out trying to get back for a second from an overthrow.
Gain and Robertson got going quickly to limit the damage and put the pressure back on thebowling side.
Canterbury brought the field in to force Otago to hit over the top and Robertson (15) holed out.
Sharp had to make ground quickly to her right and nabbed it.
Gain mistimed a lofted drive and had to go for 18.
There was a touch of panic in that shot and some madness in the reverse paddle from Inglis which cost the wicketkeeper her wicket.
The Sparks had shifted from cruise control to chaotic but managed to limp to victory.
Their next assignment is against Wellington at Molyneux Park on Thursday.
