The captain's try broke up the game, and the resolve of his team's opponents, and Otago Boys' went on to score two more tries in front of a crowd of 2000 at Tahuna Park.
It beat defending champion Southland Boys' 30-11 and gave Otago Boys' its first win in the Highlanders First XV competition.
Otago Boys' had been the dominant team in the first half but determined tackling had kept Southland Boys' in the game.
Otago Boys' had created scoring opportunities but it was not able to finish and led 11-8 at the break.
A second penalty to Southland Boys' first five-eighth Jackson Wallace evened the scores after 14 minutes in the second spell.
The game had reached a stalemate with the scores locked at 11-11 and Collins knew his team needed to produce something unexpected to get on top.
There was some smashing tackling by Southland Boys', particularly by openside flanker Nick Hayes who cut down the Otago Boys' backline behind the advantage line.
''I knew it would be a tight game and I was not worried," Collins said.
"I knew our backs could run in tries if given the chance and we had to try something to break it up."
The opportunity came when Otago Boys' was awarded a kickable penalty 35m out.
Southland Boys' expected a kick at goal and was caught off guard when halfback Josh Renton grabbed the ball and ran. He put Collins in the clear and the skipper ran 25m to score under the bar.
That try shook the confidence of the Southland players and gave Otago Boys' a seven-point cushion.
Otago Boys' rubbed in its advantage when it counter-attacked from its own 22m two minutes later. Fullback Sean Conner scored wide out and the margin was 12 points.
Otago Boys' cut loose to score a late long-range try when wing Jarrod Hewitt grabbed the ball 75m out and outpaced the defence as he ran up the right touchline.
Renton had a long pass and was an inventive halfback, first five-eighth Sam Ellis used fancy footwork as he side-stepped his way through the defence and second five-eighth Aleki Collins threw a perfect dummy to create the first-half try.
Otago Boys' had a lot of lineout options with flanker Byron Dodge and No 8 Brodie Hume helping the locks. They both made three clean takes.
Otago Boys' had a three-to-one advantage in the lineouts and the pack took five takes off Southland Boys' throws. Lock Mike McKee impressed with his work around the paddock and strong tackling.
The best Southland backs were the midfield combination of Sven Penwarden and Fraser Beck who looked dangerous with the ball in hand.
This was the third year of the competition that had been won by Southland Boys' in the first two years. Otago Boys' will play St Bedes, the school that won the Crusaders competition, in Dunedin next Saturday.
The winner of the match will be the South Island representative in the top four schools competition in Rotorua.
Collins played at centre and wore a blank jersey instead of No 13.
"We wanted to honour the memory of our centre Sua Tanuvasa who died tragically during the season," Collins said.
"We wanted to keep the No 13 for him."
Gore beat Kings 27-24 to finish third in the competition.
Waitaki Boys' beat Kavanagh College 22-13 to secure fifth and Dunstan defeated John McGlashan 29-11 to finish seventh.South Otago downed Menzies College 22-20 to claim ninth and St Kevin's thrashed Verdon College 48-0 to finish 11th.
Southern defeated Dunedin 22-19 in the premier 2 final at the University Oval.
- The scores
OBHS v SBHS
• Otago Boys' 30
Sean Conner, Eti Slater, Jarrod Hewitt, Michael Collins tries; Sam Ellis 2con, 2 pen
• Southland Boys' 11
Ryan Egerton try; Jackson Wallace 2 pen.
• Halftime: 11-8.