Amla’s 119 led South Africa to an impressive, but not overly daunting, 282 for nine in the second match at Mount Maunganui before the home side failed to get going against a bowling attack that put them under constant pressure.
With Kane Williamson and Ross Taylor out injured, none of New Zealand’s top-order batsmen did themselves any favours in the jockeying for World Cup selection as they were dismissed for 210 in 46.3 overs.
Wicketkeeper Luke Ronchi, who top-scored for the hosts with 99 in the first game, again led his side with 79 and shared in another record final wicket partnership, this time with Mitchell McClenaghan (34 not out) as they put on 76 runs.
Ronchi and Trent Boult had scored 74 runs, a New Zealand record against all countries for the final wicket, in the first game.
The visitors had won the first game by six wickets and can jump to the top of the International Cricket Council one-day rankings if they complete a clean sweep of the series in Hamilton on Monday.
Australia top the list but a 3-0 series victory will mean two more points for the Proteas, also on 113 points.
South Africa had been well set to score in excess of 300 courtesy of Amla’s 16th one-day international century and Faf Du Plessis’ 67 before the wheels fell off their innings.
Amla was dismissed in the 45th over with his side on 257 for four and exciting stroke-makers JP Duminy, David Miller and Rilee Roussouw still to come.
Duminy and Miller took the visitors through to 279 in the 48th over before a spectacular collapse when they scored just three singles off the final 14 balls and lost five wickets causing some concern at their frailty ahead of the World Cup. (Reuters)