The Taieri College year 9 A team won all nine of its games to win the South Island Secondary Schools' Development Tournament in Christchurch last week.
Taieri College teacher Karen Rosevear said it was the first time an Otago or Southland team had won either the year 9 or year 10 sections.
Year 9 A defeated Christchurch Girls' High School 24-22 in the final.
Two Taieri College teams took part in last week's tournament.
The tournament is held every year across three sections; year 10, year 9 and a combined section.
Fifty-five schools competed.
Taieri College 10 A won six of its nine games, finishing 19th.
It was the fourth top Otago school.
Ms Rosevear said all games were tight with close scores in each quarter.
''The final was a particularly tense game, befitting a final,'' she said.
In the Taieri Year 9 final against Christchurch Girls', the first quarter saw the scores tied at 6-6 and the half-time score was 13-11 to Taieri.
An equally narrow third quarter saw Taieri go into the final quarter leading 18-15.
''Christchurch Girls' came back strongly in the final quarter.
''It was a relief . . . when the final whistle went.''
