Centurion Kane Williamson and Devon Conway unfurled a record partnership one-day international partnership against South Africa to steer the Black Caps to a six-wicket victory in their Tri-Nations match in Lahore.
After opening the tournament with victory over hosts Pakistan, New Zealand are guaranteed a place in the final of the tournament being used as a warmup for the Champions Trophy ODI tournament.
Williamson showed he is primed to be a key performer after blasting an unbeaten 133 off 113 balls as the Black Caps reached 308-4 with eight balls to spare after South Africa had posted 304-6.
Opener Conway returned to form to play the perfect support role, scoring 97 off 107 balls as the pair combined for 187 for the second wicket, the highest partnership for any New Zealand wicket in an ODI against the Proteas.
Their efforts eclipsed a brilliant 150 from South African opener Matthew Breetzke, who reached the highest score by any player on ODI debut, eclipsing a 47-year-old record held by West Indies great Desmond Haynes.
Williamson went close to a record of his own, becoming the second-fastest player to reach 7000 ODI runs, getting there in 159 innings. Only former South African opener Hashim Amlas was quicker, in 150 innings.
The 34-year-old produced a series of classy boundaries all around the wicket - finishing with 13 fours and two sixes - ensuring New Zealand would chase down their second-biggest target in an ODI away from home.Playing with freedom from the outset, against a weakened Proteas attack, It took Williamson just 72 balls to get to his century, his second fastest by balls faced in ODIs.
"I think the conditions today were a bit different and we did an outstanding job'" Williamson.
"We had to work hard to chase it down. Whenever you're chasing a score like that you need partnership and it was a really good team effort. We're trying to get used to the conditions as much as possible."
Conway's dismissal 71 runs short of the target sparked a New Zealand stutter - including a third successive duck for Tom Latham - before Glenn Phillips (28 not out) joined Williamson to deliver the final rites.
Earlier, seamers Matt Henry (2-59) and Will O'Rourke (2-72) were the most successful Black Caps bowlers while spinner Michael Bracewell's 1-43 off 10 overs was the most miserly return.
Breetzke's fine 148-ball knock, which included five sixes, ended in the 46th over when he was caught at mid-on off a slower ball from Henry.
"It hasn't sunk in yet and I'm a bit tired," Breetzke said.
"The pitch was tacky and O'Rourke was really tough to face. My mindset was to bat as long as possible and give myself a chance at the end."
South Africa were missing several leading players who are not available for the series.
