The only real success for Dumbarton was the fact that the match went ahead - a fact which financially benefited the tiny third division club.
In only his second match in charge of the Sons, Jim Chapman did not have an enviable task travelling across the River Clyde to take on their SPL opponents.
To be fair to the part-time visitors, the Saints had to produce some stunning football to secure their place in the fifth round draw.
Mark Corcoran, who had previously been impotent in front of goal in Paisley, burst forth in the 16th minute to net a stunner.
On-loan centre half Grant Evans failed to get purchase on a cross from Alex Burke and the ball fell to the onrushing Corcoran, whose half volley rifled into the top corner of the net.
Dumbarton keeper David Crawford was under severe pressure as the embattled custodian had to make a series of saves from Craig Dargo to keep the scoreline respectable.
But Crawford could do little about St Mirren's second just before half-time.
David Barron had taken a speculative position on the edge of the box at the St Mirren corner and, as the ball fell to the defender, he curled a shot into the top corner and away from the flailing Crawford.
St Mirren gave a debut to new American signing Andy Dorman on the hour mark and the winger had an immediate opportunity to open his account for the Buddies, but there was still slight signs of rust as his eight-yard volley were sliced well wide of the mark.
Number three for the Paisley club came in calamitous circumstances for Dumbarton as keeper Crawford contrived to fumble Billy Mehmet's 25-yard drive into the back of the net and was promptly replaced by Anton Nugent for his troubles.