The wideman grabbed a hat-trick when Saints beat the Seasiders 5-0 at Park Hall earlier this season and was again the tormentor, breaking the deadlock in the 49th-minute when he sent a looping header over keeper Steve Cann and into the far corner from a Craig Jones cross.
The Saints rode their luck at times with Lewis Codling guilty of a glaring miss on the half-hour when he headed the wrong side of the post with the goal at his mercy.
TNS struggled to break through a five-man Black & Greens' midfield, but the hosts showed their lack of confidence after a nine-game winless run with midfielder Luke Sherbon especially profligate in front of goal.
Destined for another stint Down Under later this month, Sherbon missed three good chances in the space of a few minutes in the second-half.
But the biggest let-off came in the final moments when sub Matty Williams fluffed a clearance and Jay McCarten hammered an 18-yarder against the crossbar which keeper Paul Harrison was relieved to see rebound the wrong side of the goal-line.
And it was the Saints who scored again, deep into stoppage time, when Jones broke clear and fed Partridge, whose shot found the net via Cann's outstretched hand.
A make-shift defence, missing both regular wing-backs, was superbly marshalled by S4C's man-of-the-match Pip Baker to keep a clean sheet which pleased Saints' boss Mike Davies.