A maiden one-day hundred and a record partnership paved the way for Otago's 16-run victory against Wellington in Queenstown yesterday.
Volts captain Nathan McCullum played arguably his finest knock for the province, scoring 119 from 109 balls and guiding his side to 286 for eight.
He combined in an Otago record fifth-wicket stand of 150 with Iain Robertson and took three for 47 with the ball.
But his opposite also had a good day. James Franklin calmly went about pacing Wellington's reply with a fine unbeaten innings of 98.
With the help of debutant Alecz Day, who swatted a rapid 50, the visitor appeared well-placed.
But McCullum bowled Day and Sam Wells struck twice in the 45th over to effectively seal the game.
Wellington needed an unlikely 31 to win from the last over but fell short, finishing with 270 for nine.
The loss of Grant Elliott for 35 and Luke Ronchi before he could get going was crucial as well.
Wells captured Elliott's wicket when he top edged a pull shot. And Ronchi, who had just whacked a six to get off the mark, holed out at midwicket, gifting 18-year-old Josh Finnie his maiden one-day wicket.
Earlier, Otago made a useful start, with Wells and Ryan Duffy putting on 51 for the first wicket.
But the boundaries dried up with the arrival of Brent Arnel and Elliott at the bowling crease.
Wells was the first to crack, chopping on for 23. The in-form Michael Bracewell mistimed a pull shot and Derek de Boorder looked to flick the ball leg side but got an edge through to Ronchi.
Duffy, who was on one-day debut, showed some promise during his innings of 31. A crisp pull shot for six sticks out in the memory, but so too does his dismissal. He left shaking his head after picking out Luke Woodcock at mid-off.
Having slumped to 65 for four, McCullum and Robertson took the attack back to Wellington.
By the time McCullum called for the second power play, the Volts' situation had improved dramatically at 139 for four with 15 overs remaining.
Otago took 42 off the next five overs, during which the pair brought up their 100-run partnership from 113 balls.
Robertson got lucky once or twice and McCullum was dropped by Woodcock at cover on 75.
But the partnership continued to flourish and eclipsed the old mark of 143 McCullum shared with Craig Cumming against Northern Districts at the University Oval in 2011-12.
McCullum brought up his maiden one-day hundred when he squeezed a delivery backward of point for four.
He eventually hit out in the penultimate over, Robertson's fine knock of 62 having come to an end five overs earlier.
Finnie gave a glimpse of his potential with a brisk 30 to help the Volts get past 280.
Elliott finished with four for 46 and Arnel's two for 50 represented a tidy effort.
In the two other games, Auckland overhauled Canterbury's modest total of 199 with seven wickets in hand at Eden Park Outer Oval.
And in New Plymouth, Northern Districts held on to beat Central Districts by 13 runs after posting 297 for nine.
