Aberdeen snuffed out any hope St Mirren had of recording a Scottish Cup shock at Pittodrie as two goals in the opening 17 minutes set the Dons on their way to the fifth round.
This was a game tipped by many as one where an upset could be on the cards with the Dons hosting the Championship leaders in their first game back from the winter break.
Saints were game and pushed the Dons but, ultimately, the gulf in class between the two teams proved the difference as Derek McInnes enjoyed a winning start to 2018.
St Mirren deserve credit for their attacking approach to the game but they were punished for it by a ruthless Dons side.
Jack Ross’ team were bright and bubbly in the opening exchanges but they were undone as early as the seventh minute when the quick feet of Greg Stewart enticed Stelios Deme-triou into making a rash challenge in the box and the Saints full back got it horribly wrong as he tripped the on-loan Birmingham City attacker. Referee Don Robertson pointed to the spot and Adam Rooney sent Craig Samson the wrong way with the penalty.
The goal settled the home side and they went about their task of putting this tie to bed.
Aberdeen had identified the Saints full backs – Demetriou and Liam Smith – as areas which could be exploited and Stewart cut in from the left before seeing a shot turned away for a corner by Samson.
Samson’s save only delayed the inevitable as the home side cut through the visitors defence to double their lead in the 17th minute.
Ryan Christie and Kenny McLean exchanged passes before Gary Mackay-Steven was sent clear down the left.
The winger picked out Christie perfectly from the byline and the midfielder did not have to break stride as he fired home the second despite Samson’s best efforts.
The Dons were cruising but they shot themselves in the foot by gifting Saints a lifeline.
Stewart was caught in possession inside his own box and Buddies winger Lewis Morgan fired in an angled drive which Joe Lewis parried and Gavin Reilly reacted quickest to convert the rebound.
A nervous few minutes followed but a third goal from the Dons in the 33rd minute settled the nerves.
Saints left back Demetriou made a hash of heading a Mackay-Steven cross clear and Shay Logan took advantage, with his cross picking out the unmarked Christie who headed home.
There was an element of rustiness in some of Aberdeen’s play – with the goal they conceded one example – while former Don Cammy Smith almost took advantage of more casual play from his old club but these instances were fleeting in an impressive showing from McInnes’ men.
The next goal was going to be crucial and Aberdeen got it in style within two minutes of the second half with Mackay-Steven’s first touch taking him past Smith before he beat Samson with a stunning angled drive.
With the Dons in control Niall McGinn came off the bench for his first appearance since returning to the club and he almost capped his debut with a scissor kick volley but his effort went just wide.
In the end it mattered little. A potential banana skin for the Dons was navigated with the minimum of fuss as they booked their place in the fifth round.