Impressive forward Riley Mullany was one of the stars for Napier, scoring a hat-trick of tries.
It was all hugs and high-fives at the final whistle as the home team breathed some life back into their 2025 season.
Both Hamilton and Napier remain near the bottom of the Super 8 ladder, with one win each from their respective four matches.
Meanwhile, a day earlier, Hastings Boys’ High School First XV lost their Super 8 clash at home to Rotorua Boys’ High School First XV 34-33.
That match featured some controversy, with what appeared to be a scrum infringement from Rotorua on the final play of the game.
Rotorua went on to kick a winning penalty moments later.
Palmerston North Boys’ High School are the only undefeated team left in the competition and sit atop the ladder.
Rotorua currently hold the Moascar Cup – the schoolboy version of the Ranfurly Shield – and will next host Napier this coming Saturday.
Napier Boys’ High School 40 (Tries: R. Mullany (3), H. O’Rourke (2), H. Bain; W. Lovatt 5 conversions) defeated Hamilton Boys’ High School 29 (Tries: C. Dunlop (2), O. Guerin (2), C. Parai; J. Botherway 2 conversions)