St Mirren were without Kyle Magennis after the midfielder sustained a season-ending injury at Ibrox in midweek. Defender Paul McGinn dropped to the bench, with Tony Andreu and Ilkay Durmus both promoted to the starting line-up.
St Mirren made a positive start but it was Aberdeen who enjoyed the first real chance.
Niall McGinn's corner picked out Ash Taylor but the defender made a mess of the header and it bounced tamely wide.
Aberdeen were then nearly gifted a goal a minute later. St Mirren goalkeeper Vaclav Hladky mishit a pass inside the box to Akin Famewo, allowing Niall McGinn to nip in. The defender, though, recovered quickly to make a timely block.
The game settled down after that, with the home side having the bulk of the possession but Aberdeen posing a greater threat on the counter.
And the visitors felt they ought to have been given a penalty in the 28th minute when Conor McCarthy hauled Sam Cosgrove to the ground. Referee Don Robertson, though, was not convinced and turned down the appeals.
Aberdeen were growing into the game and, after a corner was not cleared, Scott McKenna's shot went over the crossbar with the aid of a deflection.
The best chance of the first half, though, went the way of the home side. Dylan McGeouch was slack with a back-pass, allowing Obika to run in on goal. The striker steadied himself but somehow struck the post when he ought to have scored.
Saints had one final chance before the break but McCarthy could only head Cameron MacPherson's free-kick into the arms of Joe Lewis.
The second half was competitive but again lacking in quality. Durmus had a run and shot that went well over the top, while the winger then created a chance for Andreu that Lewis comfortably saved.
Aberdeen were struggling to create anything of note, although one well-worked move ended with Lewis Ferguson stabbing a shot wide, before a Funso Ojo long-ranger was gathered by Hladky.