The Baby Blacks had to dig deep to repel host nation Italy 14-5 in Calvisano.
Playing in oppressive heat and in front of a buoyant crowd, New Zealand were held scoreless in the second half of a turgid spectacle.
The first half took more than an hour to complete.
In the third minute, Italian tighthead prop Bruno Vallesi was laid out in a brutal tackle by Mosese Bason. The injury break stretched 15 minutes.
New Zealand were penalised frequently for scrum infringements as they struggled to contain an Azzurri pack led by 142kg loosehead prop Sergio Pellicioli.
Italy threw ample numbers at the breakdown and unsettled a New Zealand team that lacked cohesion and discipline.
Winger Stanley Solomon, speculated to be a Highlanders target for next season, was yellow-carded for an illegal cleanout in the first half.
Replacement forward Randall Baker followed in the second as New Zealand conceded a dozen penalties to Italy’s four.
The Baby Blacks could take heart from a determined defensive display.
Crusaders hooker Manumaua Letiu scored New Zealand’s first try from a lineout drive that could have finished in Rome.
Influential halfback Pledger scored just before halftime with a trademark dummy and dash over 30m.
Second five Copper Roberts and lock Xavier Treacy topped the New Zealand tackle count with 13 each, followed by openside flanker Caleb Woodley with nine.
Winger Frank Vaenuku was easily New Zealand’s most lively back. The All Blacks Sevens flyer made three line breaks and charged for a game-high 97m.
Halfback Niccolo Beni scored Italy’s only try, a second-half cracker.
New Zealand, who last won the tournament in 2017, next play Georgia on Saturday.
U20 World Championship
The scores
New Zealand 14
Manumaua Letiu, Dylan Pledger tries; Will Cole 2 con
Italy 5
Niccolo Beni try
Halftime: New Zealand 14-0.
— APL/NZ Rugby
