They fought back with some tenacious defence, marshalled by openside flanker Flynn Kelly, and rocked Rotorua with two quick tries to fullback Cole Forbes and first-five Jake Malbon.
Forbes kicked a penalty to close the gap to just six points and with the final play of the match Tauranga attacked inside Rotorua's 22.
But a desperate tackle turned the ball over and Rotorua were able to clear before international referee Nick Briant blew full time.
Kelly, in his second year in the Tauranga Boys' First XV, paid the price early of going too high in the tackle but soon adjusted to be the dominant defender.
"This season has been going really well so far. There is a whole new structure around rugby at the school and a bit more of an emphasis on it than in previous years," Kelly said. "There is a lot more culture and a lot more brotherhood forming. This is our field we have to defend."
Tauranga Boys' coach Dan Goodwin felt it was a lost opportunity to knock over the national champions.
"I am disappointed for the boys. They showed good intent and they could have won. We came back but our set piece let us down and pretty much that was the difference," Goodwin said.
"We might have fallen asleep a little bit after halftime thinking the wind was going to win it for us. But I am still happy with the boys and seeing the improvement. It is about making sure we put the complete package together.
"That is our goal to keep on improving. We want that belief back in the school that we are a good rugby school."
Rotorua Boys' coach Ngarimu Simpkins expected nothing less than the full-on confrontation his side got.
"With the coaches and set-up they have at Tauranga Boys' we thought we were going to be in for a tough game and we certainly got that.
"Tauranga took their chances but we scored some beautiful tries. I think they were the best we have scored this year and it is really pleasing to see some desire coming from the boys."
Rotorua Boys' High School 24 (Jaya More, Viliami Tosi, Tama Te Aute, Hayze Perham tries; Kaleb Trask 2 cons) Tauranga Boys' College 18 (Leroy Carter, Cole Forbes, Jake Malbon tries; Forbes pen). HT: 5-5.