Caretaker boss Jamie McKenzie breathed some life into the first half when he out-muscled Neil Stephen to control a long Renton clearance before advancing to the edge of the area and sending a low curling effort just inches past James Butter's left-hand post.
The closest we came to a goal in the opening period followed a spill by James Butter, Adam Nelson tried to chip the stranded keeper from 30 yards but his effort struck the underside of the crossbar and landed on the goal line before being cleared.
The breakthrough came eleven minutes after the break with a goal of pure simplicity. Stuart Cumming made his way towards the corner flag on the right wing before cutting back onto his left foot and delivering a cross perfectly onto the head of Martin Johnston who, from seven yards out, flicked it deftly into the top corner of the net.
When a City corner came back out to the taker Martin Lauchlan he weaved his way towards the goal line before cutting it back for Jamie McKenzie but he rattled Butter's right hand post with his side-footed effort.
Montrose went in search of an equaliser in the final half hour but they rarely threatened Keiron Renton's goal with the big keeper making a handful of routine saves in the closing stages.