But that was long enough for Napier to storm back into the game with two well-taken tries as Tauranga stepped off the defensive intensity for the only time in the game.
With the lead cut to 22-15, Tauranga began the second spell with clear plans to use the wind behind them for field position, which first-five Israel Turner delivered accurately.
Winger Steve Masters showed plenty of determination to win the race over the goal line for Tauranga's fourth bonus point try and a decisive 27-15 lead.
As the weather turned for the worse, the battle up front intensified. Watching intently on the sideline was former All Black and Tauranga Boys' First XV forward Jarrad Hoeata, home from a season playing for Cardiff Blues in Wales.
More Napier ill-discipline proved costly as they received their third yellow card after a dust-up near the Tauranga line, and Tauranga cruised home to a fine victory.
For good measure, Tauranga Boys' defeated Napier Boys' 20-17 in the early match in their Super 8 Second XV clash.
Both Tauranga Boys' Super 8 teams are at home the next two Saturdays with the visits of Palmerston North Boys' (June 27) and Hamilton Boys' (July 4).
Tauranga Boys' College 30 (Sammy Veikoso, Harris Williams, Kini Ormsby, Steve Masters tries; Sam Takai 2 cons, 2 pens) Napier Boys' High School 18.
Second XV: Tauranga Boys' College 20 Napier Boys' High School 17