At the Balclutha Showgrounds on Saturday, it overcame the cold and wet conditions to play attractive running rugby in a 77-7 win over Central Southland College.
South Otago attacked from all quarters and scored 13 tries. Winger Osca Goodlett bagged three.
The other key player in the South Otago team was centre Matt Whaanga, who continued his prolific scoring run with 22 points from two tries and six conversions.
South Otago dominated from the start, led 41-7 at halftime and added 36 points in the second half.
Other top performers were prop Tayler Hammer and No 8 Joel White.
King's High School kept hold of the ball in the second half to grind out a 15-3 win over Menzies College in wet conditions in Dunedin in the top eight competition.
King's led 5-3 at halftime.
In the first half, King's kicked away too much ball, but it tightened its grip on the game in the second spell by holding on to the ball.
King's dominated the lineout through the work of locks Taylor Cumberland and Liam Taylor and flanker Logan Garforth.
Otago Boys' High School continued its unbeaten record when it scored seven tries to beat John McGlashan College 43-5 at the University Oval.
Otago Boys dominated up front through the driving play of its pack and the hard tackling of flanker Matt Heffernan.
The best try of the game was scored by first five-eighth Sam Porter, who beat six tackles on his 60m dash for the try.
Otago Boys' is playing precision rugby and this was demonstrated when winger Matt Jones scored after a set piece move from a scrum.
Dunstan High School overcame the rough conditions in Riverton, when it scored eight tries to beat James Hargest College 50-7 in the bottom six competition.
Winger Logan Cornish and centre Canaan Napier both scored two tries. First five-eighth Jayden McLew kicked five conversions.
Southland Boys' High School beat Mt Aspiring College 50-7, while St Kevin's College beat Waitaki Boys' High School 33-12 in a Friday interschool. The clash between St Peter's College and Gore High School has been deferred.
