The South African-born left-hander top-scored for the visitors with 73 and shared in a 118-run partnership with Peter Younghusband (49).
The visitors had slumped to 75 for five, so had to fight for the title. Ollie Newton clipped a four through mid-wicket to seal the win in the penultimate over.
Earlier, the Volts had to claw their way back into the match with a gutsy eighth-wicket partnership, posting 234 for eight.
But the fightback came from Michael Rippon and Christi Viljoen. The pair added 146 runs, breaking the previous highest New Zealand eighth-wicket stand of 121.
Rippon dragged the Volt past 200 with 82, and Viljoen struck a career-high unbeaten 87.