This was a case of subduing a stubborn, but ultimately punchless Queen of the South before providing the embellishment.
Lewis Morgan proved the touchstone, constructing the opening goal for Danny Mullen and contributing an excellent free-kick goal after Queens had threatened to spoil the day.
Mullen put St Mirren in front with a calm finish after Morgan had galloped past a cluster of defenders to set up the chance, but Jordan Marshall equalised when he exchanged passes with John Rankin before drilling the ball low past Craig Samson.
Morgan put St Mirren back in front with a precise free-kick beyond Jack Leighfield shortly after half-time.
Gary MacKenzie wasted a great chance shortly afterwards before Kyle Magennis took matters into his own hands, driving forward to send a terrific strike past Leighfield.
There was no way back for the home side and Leighfield prevented a fourth late on when he denied Jack Baird.