A red card for Teddy Jenks early in the second half changed the course of a game after the Dons had been ahead at the break but the hosts came from behind to claim the three points.
Stephen Glass made three changes to the side beaten last week by St Johnstone as the Dons looked to return to winning ways in Paisley. Jonny Hayes, Teddy Jenks and fit again Ryan Hedges were all recalled to the starting line-up. Austin Samuels, and Jay Emmanuel-Thomas were on the bench, Funso Ojo missing out altogether. Dylan McGeouch and Gary Woods returned to the matchday squad on the bench in place of Niall McGinn and Tom Ritchie.
There was just one change for St Mirren after their 2-2 draw at Hibs last weekend, Ethan Erhahon replacing Dylan Reid in midfield.
With Aberdeen playing into a stiff breeze, the hosts won a first minute corner, Joe Lewis coming through a clutch of bodies to punch decisively clear.
Aberdeen were on the attack on seven minutes, a great ball out from the back from David Bates getting Jenks away down the right. Christian Ramirez, a couple of defenders and Alnwick all converged on the low cross but with Hayes swooping down on the loose ball, Alnwick was quick to recover and smother it.
Lewis was alert again when a ball over the top beat the offside line, the goalkeeper swiftly off his line to snuff out the danger. On 14 minutes though, the Buddies were ahead. Lewis' clearance was cut out on halfway, Erhahon able to play a diagonal ball to Ronan who got away from Bates and fired in an angled drive that took a deflection off the centre-half to see it sneak inside the near post.
It took just four minutes for Aberdeen to level it up. Calvin Ramsay curled in a free-kick from the right. Ramirez got up to win the header that was going back across the face of goal, but it clipped Scott Brown's heel and rebounded into the net, the skipper's first goal for the Dons and a timely one too, however little he knew about it.
It should have been 2-1 on 20 minutes, Jenks played through and in on goal. As he looked to pull the trigger, Fraser came across to get in a fine block to deny him. Seven minutes later, Jenks was in the book for a late challenge on Fraser.
A dangerous cross from Hayes on 28 was well defended by Shaughnessy, extending a long leg to take the ball away from Ramirez, on the prowl in the six yard box. Fraser was then booked on 33 minutes, hauling down Hayes with a rugby tackle.
From the free-kick, the Dons were in front with a brilliant diving header from Ramirez, getting himself into space away from Fraser as Brown blocked off the defender. From there, he bulleted his header back across goal and into the far corner from Ramsay's well placed delivery.
It was nearly three on 36, Jack MacKenzie floating a cross to the back post, Lewis Ferguson looping a header back across goal, Hedges not quite able to get the finishing touch as he slid in.
Half Time: St Mirren 1-2 Aberdeen
St Mirren made a good start to the second half, Tanser whipping in a low free-kick from the right, Lewis reacting superbly to bat the ball away to safety at the near post, a terrific save. From there, Aberdeen were back in the groove, slicking the passes around nicely and dragging St Mirren all over the pitch. Ferguson was unlucky to be booked on 50 minutes as he jumped with Shaughnessy.
Within a minute of that, the complexion of the game changed, Jenks fractionally late on a tackle and collecting his second yellow as a consequence, the Dons down to ten for the last 40 minutes of the game. St Mirren reacted by bringing on Main for Erhahon on 56 minutes.
The equaliser wasn't long coming. McGrath played the ball into Ronan on the edge of the box. He dummied to shoot, won himself space away from Bates as a result and laced a ferocious shot across goal and into the far corner.
On 61, the Buddies were in front. Hayes' clearance was charged down and found Fraser. He looped a cross into the box, Main running in front of Lewis a dozen yards out, both of them missing it, the ball nestling just inside the far post.
Ramsay showed the Dons were still in it on 63 minutes, cutting inside from the right and sending a searing shot across goal and just inches wide of the target with Alnwick beaten.
Brown was next in the book on 66 minutes for pulling Brophy down. It could have been four from the free-kick, Ronan ghosting away from Ramsay and getting in at the back post to get on the end of Tanser's ball, Lewis making a brilliant save at point blank range.
Samuels and Emmanuel-Thomas replaced Hedges and Ramirez on 72 minutes, McAllister coming on for the home side in place of Millar at the same time. Two minutes later, Fraser was replaced by Flynn.
St Mirren were close again, Tanser slinging a cross through the six yard box from the left, Brophy poking the ball wide at the back post on 77. Within two minutes Ferguson volleyed the ball a fraction wide from the edge of the box with Alnwick having long since given up on getting anywhere near it.
Brophy was the fourth St Mirren player to be replaced on 83 minutes, Dennis coming onto the field. Five minutes from time Main had a chance to seal it, up to a header at the back post but he put it well over the bar from a great position.
Ramsay was next to get booked after a tug on Main's shirt on halfway, Hayes then carded for a lunge, underlining Aberdeen's frustration as another game slipped away from the Dons.