The result leaves St Clair at the top of the table with 14 points and 22.5 games, holding a four point and three game lead over second placed Otago Blue.
Chisholm Park won its second match, downing Island Park on the Waldronville course 3.5 2.5, while Taieri, playing at home, beat Otago Gold by the same margin.
After losing two early matches, Otago Blue had to beat St Clair to keep in touch with the Corstorphine golfers but it was not to be.
Nick Borren beat Connor Ross at No 1 in 14 holes while No 4 Tyrone Ratahi gave the home team its second win at the expense of St Clair's Jakob Bleach.
At No 6, Jason Hughes beat Michael Ormandy for Otago's third win but Brandon Hodgson, Michael Smith and Daniel Elder were all beaten to tie the contest.
Smith has played his last game for the team before a back operation which will hopefully allow him to compete with little or no pain.
For St Clair, Brent McEwan was not available as he was eagerly awaiting the birth of his second son. Otago Blue was missing Duncan Croudis.
At Island Park, Nicholas James posted the first win for the home team, carding six birdies to beat Peter Rae 4 and 3, while Chisholm's Mark Collie made it one win each, beating local Michael Wray 4 and 2.
Kelly Adams won Island Park's second match with two holes to spare at the expense of Conor Jamison, while Cody McMullan (No 1) and Sean Geary (No 3) made it 2-2.
The contest looked set to be a tie but Chisholm Park No 4 Kyle Geary had other ideas. He was three down with four holes to play but fought back, winning 15, 16 and 17 and making par on the final hole to secure a valuable half with Gary Creedy and give his team a narrow win.
After a superb start, Otago Gold is now struggling playing away from home. It fell to Taieri, which notched three wins and a half.
At No 1, Harry Smith (Otago) was too good for Taieri's Mark Andrews. Murray Edgar beat Taieri No 4 Ian Boath, and No 2 Jeremy Morgan halved with Callum Stringer.
But all other matches went to Taieri, as Elliot Hornbrook, Henry van Turnhout and Brent Reid posted good wins.
This Saturday, Otago Blue hosts Island Park, and the Blue golfers will be keen for the Otago Gold team to beat St Clair at Balmacewen to help their cause. Chisholm Park hosts Taieri.
