Saints introduced Ryan Stevenson for Paddy Connolly as the only change in the starting ine up against Stranraer who listed former Saint Harry Curran on the bench.
After kevin Cuthbert came to the rescue in the 6th minute clawing away a Finlayson volley, Saints took the lead in the 17th minute when Ryan Stevenson pounced on a short headed passback. His low cross into the box eluded everyone but was picked up by Marc McCulloch who rifled the ball high into the net.
The lead lasted only ten minutes however - a lightening quick break after a failed Saints corner saw Harty with a chance to fire in on goal and he was delighted to see his effort deflected past Cuthbert by the unfortunate McCulloch.
John Robertson and Ryan Stevenson both had chances before the break which they couldn't take.
The second half was a tame affair with wayward shots from the likes of Hartley and Riley the best Saints could muster while Stranraer rarely troubled Cuthbert.
Extra time then (much to the frustration of the 40 hardy souls who had travelled down from Perth) but hey were rewarded in the 98th minute when substitute Chris Hay fired in a shot from the edge of the box which caught a defender's leg and eluded home keeper Hillcoat. Harty should have levelled for the Stair Park side after 103 minutes when he burst into the box but shot wide when it seemed easier to score. The tie was sealed in the final minute of extra time when Hay turned a Riley cross from the left into the net. Saints: Cuthbert, Robertson, McCulloch, McCluskey, Murray, Maxwell, McCann, Reilly, Hartley, Stevenson (Parker 55), Russell (Hay 75). Subs not used: Dods, Connolly, Main.