The defending champion posted 124 for eight with Aimee Watkins clipping a rapid 51 at the top and Sara McGlashan chipping in with 30 from 23 deliveries.
But Otago chased the target down with ease. White Ferns all-rounder Suzie Bates whacked five fours in her innings of 42 and overseas player Natasha Miles (26 not out) and Jenny Jackson (20 not out) guided the home side past the target with an over to spare.
Miles' responsible innings completed a successful Otago debut for the Hong Kong all-rounder. She took three for 18 from four overs and removed the dangerous Watkins and McGlashan.
The pair were threatening to take the game away from the Sparks with a 69-run stand for the second wicket.
Sarah Tsukigawa claimed two wickets and Bates and Clare Taylor took a wicket apiece in a satisfying bowling effort.
Central made a good start in the field with Malorie Bartosh-Short bowling the experienced Tsukigawa for a second-ball duck. But Katey Martin and Bates quickly got the run-rate heading in the right direction and combined in a 56-run stand for the second wicket.
Batting at No 4, Lisa Grant played a useful cameo with 16.
The teams play a one-dayer in Invercargill today and another twenty/20 fixture on tomorrow.
