Uncapped fast bowler Mitchell McClenaghan took the top order off the South African A side as the New Zealand cricketers won their Twenty20 warm-up match in Pietermaritzburg.
New Zealand posted a modest 140 for seven after winning the toss and batting.
The South African second stringers were soon in deep trouble at 23 for four limping to 116 for nine to give the tourists a 24-run win.
The left-armed McClenaghan, from Auckland, took three for 19, opening the bowling and sending down his full quota of four overs in a single spell.
McClenaghan says captain Brendan McCullum told him to just bowl as fast as he can, while bowling coach Shane Bond wanted him to keep to his lenghts and let the ball do the work.
Left-arm spinner Ronnie Hira took three for 35.
New Zealand captain Brendon McCullum hit 32 and Colin Munro made 39 as the Black Caps recovered from a poor start in which they lost their first three wickets for 44 runs in almost eight overs.
The first of three Twenty20 internationals is in Durban on Saturday morning.