Southland Boys beat Waitaki Boys 24-8 in the final of the Zero Fees/Otago Daily Times-sponsored competition at Rugby Park.
Waitaki Boys manager Craig Sturgess was proud of the team's efforts during the season.
"The boys won four of their five interschool games this winter and beat both Southland and Otago Boys on their way to the final," he said.
"Although we would have liked to have our school name printed on the cup in the inaugural year, we have to be proud of the way the boys played to make the final.
"But we were beaten by a better team on the day."
For Waitaki Boys, tighthead prop Jarrad Plackler had an outstanding game, and loosehead prop Craig Robinson also shone, while halfback Tyron Davies scored a first-half try when he charged down a clearing kick in the first half.
Southland Boys led 6-5 at the break then applied the pressure to score two second-half tries and 18 more points.
A key player for Southland Boys was first five-eighth Scott Eade, who kicked five goals and scored 14 of Southland Boys' points.
He controlled play with a sound kicking game and organised the backline.
No 8 Sam Winsloe was a strong ball carrier and made four vital turnovers at the breakdown.
Southland Boys will play St Bedes College (Christchurch) in Invercargill next Saturday for the right to represent the South Island in the national secondary schools top four competition.
• Southland Boys 24 (Javan Fa'amoe-Ioane, Zac Kelly tries; Scott Eade conversion, 3 penalty goals, dropped goal), Waitaki Boys 8 (Tyron Davies try; Brad McKenzie penalty goal). Half-time: Southland Boys 6-5.
