The home side took the lead in the ninth minute when a Paul Murphy cut-back was met by John Paul McBride, and although his shot from 25 yards was not crisply struck it still beat the Montrose keeper Andy Reid.
The Gable Endies equalised through a Greg Henslee looping backward header that caught home keeper Willie McCulloch out of position.
The home side took the lead once more through a Tommy Sinclair header from a McBride corner. They extended their lead when Colin Cramb coolly lobbed the ball over the advancing Reid to make it 3-1.
The second half saw Joe McAlpine make it 4-1 with a 35-yard daisy-cutter that swerved in at the base of the post.
Montrose scored their second when Kevin Webster headed home after Willie McCulloch had spilled a Barry Donnachie cross.
Any chances of a comeback were ended by Stenhousemuir substitute David Templeton when he made it 5-2 with a header from a Joe McAlpine cross.
The 16-year-old added a second with time running out when he timed his run perfectly to lose his marker before heading a driven Marc McKenzie cross into the net from close range to seal a fine performance by the Warriors.