The Dunedin school tasted defeat for the first time this season when it was beaten 31-5 by St Kentigern College in the final of the New Zealand secondary schools competition in Auckland.
"We played into the strong wind in the first spell and had them under the pump when we dropped two passes," Otago Boys' coach Ryan Martin said.
"We made little mistakes and they pounced on us. It was a very hard game."
The game was played in a cauldron of 5000 spectators, with most backing the home team. There were also 100 OBHS old boys living Auckland who wore the school rugby jersey.
"It was the first time we had been in a game of this intensity," Martin said.
Martin praised his front row of Ryan Williams, Sekonaia Pole and Jermaine Ainsley, who matched a St Kentigern front row that included two props who weighed 120kg. One of them, captain Sione Mafileo, was a member of the New Zealand secondary schools team last year.
Martin also praised centre Sio Tomkinson (16), one of the youngest players in the game.
St Kentigern was unbeaten in 20 games this season, while Otago Boys' won 24 of its 25 games. Eleven members of the OBHS squad will be back next year.
St Kentigern scored five tries to one and got stronger as the game went on.
The match was marred by a strong wind which blew down the ground the whole game. St Kentigern had the first use of the wind and was up 19-0 at the break, and though Otago Boys' scored early in the second half, the Auckland school always looked comfortable.
Otago Boys' made too many errors at the set piece, and when it conceded two tries within as many minutes in the second half, it was game over.
The home team got a roll on with its big forwards and the Otago Boys' lineout was all over the place in the second half. Key forward Josh Dickson was hampered by a dislocated thumb and struggled to impose himself.
Otago Boys' cause was not helped in the first half when lock Shay Kerry was yellow-carded for allegedly throwing a punch.
The only bright spot for Otago Boys' came soon after halftime, when midfield back Aleki Morris scored his 35th try of the season.
But the momentum then swung to the home team, as its best player, second five-eighth TJ Faiane, broke the defence and scoring a 50m try in the second spell. He was named the MVP of the top four competition.
The best Otago Boys' players were prop Ryan Williams, No 8 Alex Fitzgerald and Tomkinson.
Eight members of the Otago Boys' First XV are triallists for the New Zealand secondary schools team to be announced this week.
First XV
National final
St Kentigern College 31
Dillon Wihongi 2, Broc Hooper, Samuel Nock, TJ Faiane tries; Hooper 3 con
Otago Boys' High School 5
Aleki Morris try
Halftime: St Kentigern 19-0.
