Saints boss Gus MacPherson will be extremely disappointed that his side didn't shown more invention, as they had a nervous Aberdeen side on the back foot for much of the second half prior to conceding the opening goal.
Five minutes gone Aberdeen created a half chance when a Sone Aluko shot from the edge of the 18-yard box was held by Mark Howard. Aberdeen midfielder Derek Young played in a deep cross from the right on ten minutes finding the head of Andrew Considine, whose effort at the far post fell straight into the arms of Howard.
Aberdeen created another chance on 19 minutes from a Charlie Mulgrew corner. Howard came and missed the ball, which fell to Scott Severin whose six-yard effort was blocked on the line and turned away for a corner by John Potter.
Aberdeen ought to have gone ahead in 34 minutes. From a Mulgrew free-kick the ball was headed on by Lee Miller, but Considine somehow missed an open goal.
As the game approached the half-time whistle a Miller free-kick from the edge of the area was charged down by Howard, with no Dons strikers following to knock the loose ball home. Gary Mason hooked the ball away from danger.
Upon the re-start the game quickly deteriorated with aimless passing from both sides the order of the day.
At least during this second period the visitors were showing more adventure, throwing players forward in support of strikers Jim Hamilton and Billy Mehmet.
Dons fans showed how restless they had become when another dreadful pass into the St Mirren half was met by a chorus of boos from the stands.
With 25 minutes of the second half played we finally had the first shot on target of the entire half, with Andy Dorman moving on to a Mehmet knock-down before firing in a 25-yard effort which Jamie Langfield comfortably held at the second attempt.
Aberdeen did produce an opening in 76 minutes. Aluko created space for himself on the left before delivering a great cross and Richard Foster got ahead of his marker, but his glancing effort fell just wide of the upright.
Aberdeen made the breakthrough in the 80th minute. Severin and Mark Kerr combined down the right with the latter drifting inside Franco Miranda before his intelligent pull-back fell into the path of Considine, who gleefully lashed the ball home from 14 yards.
The home side netted a late second as the visitors were caught pushing men forward at the other end.
A clever reverse pass from Miller found Aluko, who gathered the ball before racing 30 yards to easily slot the ball through Howard's legs and into the net.