Jamayne Isaako led New Zealand's attack in Christchurch, scoring a hat-trick and kicking 13 of 14 conversions in an 82-16 win over the Cook Islands.
The 30-point haul helped the Kiwis claim their first Rugby League World Cup victory, after a two-point loss to Australia in the opener left them without fullback Kalyn Ponga, who broke his arm.
Isaako, the NRL's top point scorer in 2026, was among several standouts in front of a sold-out home crowd at the tournament's only match across the Tasman.
Christchurch debutant Tanner Stowers-Smith scored twice, while Casey McLean and Ronaldo Mulitalo also crossed for doubles.
New Zealand led early, but Cook Islands winger Esom Ioka scored three tries to give the visitors a 16-12 advantage before the hosts regained control.
"We got punched in the face," Kiwi coach Stacey Jones said of Ioka's quickfire hat-trick.
Cook Islands coach Karmichael Hunt said the tournament could help talented young players earn NRL opportunities.
"Some of the stories from my team, they've got to get a lot of belief in their own ability and who knows what the future holds for some of them?" he said.
Captain KL Iro also described the match as a valuable chance for young players who were off contract and trying to establish their futures.
New Zealand will play Fiji on the Gold Coast on Saturday, while the Cook Islands face Australia in Townsville to complete pool play.