In a keenly-contested encounter – three of the four matches went the full distance – Prestonfield won 3-1 to leapfrog their opponents.
After four matches, Prestonfield are now a point clear of Liberton, with Craigmillar Park two points further back after they won at Duddingston, who are now bottom.
Prestonfield have also replaced Liberton at the top of the junior table after beating them 2-0.
Duddingston are stuck at the foot of that league as well and have yet to record a victory in either event.
Prestonfield 3, Liberton 1: M Crombie and I Highley bt S Doyle and K Cantley one hole; S Johnston and L Blyth bt J Hunter and C Munro one hole; J Riddel and K Smith lost to I Neilson and G Scott 4 and 3; A McHardy and R Myles bt D Kerr and R Munro one hole.
Duddingston 1½, Craigmillar Park 2½: J Shepherd and D Gilmore halved with A Robertson and C Murison; S Speakman and M Hymers lost to S Scott and A McDonald 6 and 5; J Malone and S Dickson lost to P Mackay and B Love two holes; S Knox and D Brogan bt D Walker and D Michie 5 and 3.