Brechin started well and after seven minutes Kevin Byers intercepted a bad pass from Hugh Murray and shot wide from 30 yards.
Three minutes later John Baird headed on to Gary Twigg and he shot wide on the turn.
Brechin continued to press and after 13 minutes John Ward headed wide from a Byers corner.
However, it was St Mirren who opened the scoring in 23 minutes, Ward was adjudged to have fouled Andy Dorman and Jim Hamilton scored from the spot.
St Mirren looked for more and Dennis Wyness blazed wide from a Hamilton pass.
After 37 minutes home keeper Chris McCluskey made a brave save at the feet of both Dorman and Wyness.
In 38 minutes McCluskey fired a clearance against Hamilton and had to save the ball from entering the net.
Brechin equalised just a minute into the second half when a cross from Willie Dyer was headed down by Twigg and Neil Janczyk slammed a half-volley high into the net.
Brechin's tails were up and in 54 minutes the ball broke to Darren Smith and his drive flew inches over.
The Buddies regained the lead in 56 minutes when keeper McCluskey failed to hold a cross and Wyness sidefooted the ball into the net.
St Mirren almost made it 3-1 when a drive from full-back Jack Ross forced an outstanding save from McCluskey.
Brechin refused to give up and they thought they had equalised in 69 minutes through John Baird, but the flag was up for offside to stifle the home celebrations.
Just a minute later a disastrous mistake by McCluskey, when he got into a tangle with Ward, presented Hamilton with the chance to make it 3-1.
Brechin kept battling and after 81 minutes a Janczyk free-kick forced a great save from keeper Mark Howard. The resultant corner was played in and Smith shot wide.