It was a second defeat of the season in Paisley for a well below par Aberdeen side who missed a golden opportunity to put some pressure on Hibernian and Motherwell.
There was just the one change for the Dons following the 3-0 win over Edinburgh City at Pittodrie on Saturday. With Jonny Hayes injured, Dean Campbell replaced him at left-back. Jack Milne was added to the bench from Saturday's game.
St Mirren won 2-0 at Ayr United in the cup last weekend and made three changes to their starting XI. In came Eamonn Brophy, Jamie McGrath and Connor Ronan in place of Ethan Erhahon, Kristan Dennis and Kyle McAllister, those three all dropping to the bench.
St Mirren were on the attack in the opening minute, David Bates producing a diving header to cut out a dangerous cross. From the corner, Henderson slashed a shot over the bar. A second corner for the hosts on four minutes saw Fraser head wide from six yards out as the Buddies started well.
It was nervy stuff from the Dons and Kiltie was next to try his luck, a ferocious shot from a tight angle going wide on eight minutes as Aberdeen struggled to get into the game. A poor backpass from halfway from Christian Ramirez almost had Brophy in on goal on the quarter hour, Lewis sprinting off his line to just beat him to the ball.
The first bit of quality passing football the Dons had produced so far resulted in a 23rd minute corner, but the home side were able to clear their lines comparatively easily. Four minutes later, Lewis Ferguson was given space to come forward into and he drove a left foot shot across goal that drifted just wide.
Aberdeen were beginning to tick now, picking up the pace, Ferguson and Ryan Hedges combining to release Ramirez on 29 minutes, his shot charged down. Much better from Aberdeen though.
A flowing move on 44 minutes ended with Calvin Ramsay spearing in a cross that Alnwick tipped behind for a corner. Played short, it came to nothing, summing up what was, in truth, an eminently forgettable first 45 minutes.
HALF-TIME: ST MIRREN 0 ABERDEEN 0
With a brisk breeze behind them, the Dons started the second half brightly, good control of a long ball forward by Ramirez allowing him to link up with Hedges. He picked out Scott Brown but he scooped his shot just over from 20 yards in the 48th minute.
Brown was close again a minute later, Campbell's teasing cross taken out of his goalkeeper's hands by Dunne's header, the ball reaching the captain beyond the far post, his shot from a narrow angle kicked away off the line.
On 61 though, the Dons were behind, Ronan given far too much time and space on the left edge of the box. He took full advantage of it, producing a fine curling finish across goal and into the far corner, giving Joe Lewis no chance. Aberdeen responded immediately by withdrawing Hedges for Jay Emmanuel-Thomas.
Campbell took the game's first yellow card on 70 minutes, seconds after Power had scythed Jenks down. A minute later, Brophy was replaced by Greive. The Dons looked to inject some pace into things with Connor McLennan replacing Jenks on 73 minutes. The slew of substitutions continued when the Dons brought on Matty Kennedy for Ramsay and the home side brought on Erhahon for Ronan on 78.
Bates had to produce a strong challenge in the penalty box as Greive looked threatening a minute later following a misunderstanding between Aberdeen's centre-halves, symptomatic of a disjointed Dons display.
Tanser collected a yellow card as the game edged into time added on, but even as the Dons loaded the box nothing would fall for them, the hosts hitting Aberdeen on the break, Campbell having put a Kiltie shot behind for a corner.