The victory ended an excellent week for United who, on Wednesday, reached the last four of the League Cup at the expense of Hibs.
The hosts came close to grabbing an early lead when Paton’s curling free-kick was met by Calum Butcher whose downward header was cleared off the line by Kenny McLean.
At the other end, Callum Ball was denied by keeper Radoslaw Cierzniak and moments later Saints skipper Marc McAusland headed Gary Teale’s corner just over the bar.
The visitors came close again through Adam Drury whose low shot was turned round a post by Cierzniak.
But, on the stroke of half-time, United went ahead through Paton. Stuart Armstrong’s diagonal pass found Aidan Connolly whose cross clipped Jeroen Tesselaar before falling to Paton to sweep home from 12 yards.
Saints almost levelled on 53 when Cierzniak saved well from Drury.
Yet four minutes later United added a second. Aidan Connolly’s header from Butcher’s lofted pass was parried by keeper Marian Kello and Ciftci turned in the rebound from close range.
And the three points were safe on 73 as Telfer ran on to Connolly’s through-ball to slide his shot past a diving Kello.