In the first half waves of New Zealand attacks brought no reward as they were time and again met by a startling defensive line.
When the two sides met in the pool stages in Paris last year Ireland were brushed aside much more easily by the big loose forwards Messam and Setephano.
This year, however, there was clear evidence that the Irish had not only gone away and studied the tapes, but also their own defence.
For all their advantage in the attacking possession column New Zealand only led 6-0 at half time, two Miah Nikora penalties the difference.
Conor Gildea, his opposite number at fly half for Ireland, had kicked from hand beautifully for much of the half to ease the sometimes tumultuous pressure on his grateful forward pack.
The Irish backs too - for once not out-sized by their kiwi opposition - repelled wave after wave of attack, and probed for space themselves, albeit to no avail.
The second half brought points for Ireland - six from the boot of wing Eamonn Fitzgerald - but more points too for the men in black, who grabbed a try on the left through Luke Devcich following good work from left wing James Somerset.
Two quick tries for replacement wing Joseph Utiera then yielded further points to take the total to 23-6.
Match report courtesy www.irb.com
First roundresults from world under-19 rugby union championship in Durban on Saturday March 27th:
Australia 62 Japan 12 New Zealand 30 Ireland 6 South Africa 29 Argentina Wales 52 Italy 9