Montrose never fully recovered from the early triple whammy of conceding a penalty and losing a player and a goal within four minutes.
The Links Park men managed to restrict their opponents to just one more goal but the damage was done in just 90 seconds when Garry Wood miscued a pass to the home side’s Paul Woods.
Woods sent Chris Duggan through on goal where he was upended by keeper Stuart McKenzie, who received his second early dismissal of the season.
After a short delay, sub goalie Lucas Birnstingl came on for the unfortunate Bryan Deasley and Duggan slotted the spot-kick.
The replacement shot-stopper kept out efforts from Shaun Fraser and Ciaran McElroy before being beaten right on half-time when David MacGregor forced home a Darren Miller corner.
The Gable Endies were content to see the game out with no more damage although they did go close to scoring themselves through a Graham Webster shot and a Paul Watson free-kick that also worried the home defence.
Birnstingl said: “The sending off was just one of those things that can happen to goalkeepers. The goal at half-time from the set-play was really disappointing as if we went in at just 1-0 we would have had a chance of getting back into things.
“We defended really well in the second half when it was wave after wave of their attacks.”
Manager George Shields said: “Stuart pulled his hands away but the boy caught against his elbow.
“If it had happened at the other end, I would have been looking for the same decision. It was obviously disappointing but it was the second goal that has killed us stone dead.
“The second half was damage limitation where we had to get the balance right between not losing more goals and trying to hit them on the break.
“We had a chance early on when Graham hit the bar but after that they dominated possession. I was happy with the second-half performance.”