The final will be played towards the end of August when the Corstorphine golfers will meet either North Otago or Chisholm Park, which finished second and third respectively in the just-completed round robin.
These two teams will play off for the other finals spot at a date yet to be arranged.
St Clair was clearly the dominant team this year, dropping only 4.5 games out of a total of 24 during the series.
No 1 Brent McEwan has enjoyed a good series but was tested on Saturday by Otago's apprentice greenkeeper, Tyrone Ratahi, who played sub-par golf in the wintry conditions.
McEwan was forced to make birdies to stay ahead of Ratahi, who had his putter working overtime.
Andrew Hobbs, Paul Brouwer and Michael Minty posted convincing wins for St Clair while Thomas Facer and Luke Murdoch had 4 and 3 wins for Otago.
At Balmacewen, North Otago downed Otago B by a two-game margin to finish second in the series, with Chisholm Park third after a bye in the final round.
It was a pleasing result for the Oamaru and Park golfers who have languished at the bottom of the points table in the past.
But it will be back to the drawing board for the Otago A and B teams.
The former won the coastal and provincial titles in style last year but, this year, Otago A finished fourth with three draws and a loss while Otago B took the wooden spoon.
