The men won 4-2, but had to win three consecutive tiebreakers at the end of the doubles to secure the title from a gallant McGlashan team. The women, through Georgia Hume and Harriet Dorrington, took three straight-sets wins over St Clair.
Fortunes in the men's final changed all afternoon, with five of the six matches going to three sets, but Harbour was left with the task of winning both doubles after dropping sets in both their earlier singles wins.
They split their strength, pairing No 1 with No 4, and Aaron Hicks and Mike Smith held their nerve in the third-set match tiebreak which they won 10-6 against Paddy Ou and Andrew Mitchell.
Campbell Higgins and Ryan Eggers needed to win a second-set tiebreak just to stay alive against Kyu Kim and Mitchell Sizemore and, when that was achieved, the whole season came down to a 10-point tiebreak.
The Harbour pair were always well ahead after racing to a 5-0 lead and held on to win it 10-6 amid increasing vocal encouragement as the finalists from other grades gathered in the fading light. The tie had started with Mitchell using his serve and volley to bustle Eggers, who was unable to produce his usual fight, and went down 6-3, 6-1.
Smith showed his fitness and the ability to manage a rally, although Sizemore played plenty of impressive drives, often in a losing point. Smith won 6-2, 6-2, 6-4. Higgins overcame a 0-6 first set and won the next two 6-2, 6-4 against Kim.
The schoolboy was perhaps guilty of lacking the intensity needed at the start of the second set but, in the final part of the match, both players pushed hard. Ou continued his giant-killing feats at No 1 by outstaying Aucklander Hicks 6-2 in the third set after the first two were split 6-4, 6-7.
He has now beaten both of the higher-ranked opponents in successive weeks to claim a virtual top ranking in Otago at the age of 15.
Hume repeated her Otago Open final win over Scarlett Cuthill in winning 6-3, 6-3. Cuthill was able to match Hume for power but not quite the consistency. Dorrington was too solid for Jessika Brass, dropping only one game and the doubles was 6-1, 6-2 to give Harbour a part share of the double title.
