Aberdeen were ruthless in front of goal, doubles from Watkins and Ramirez thumping St Mirren as the Dons got themselves back into the top six at a rain sodden Pittodrie.
Following the 2-0 win over Livingston on Wednesday night, Stephen Glass was able to name an unchanged starting XI for the visit of St. Mirren. On the bench, fit again Declan Gallagher replaced Jack Gurr in the afternoon's only change.
There were three changes for St Mirren after their 0-0 draw in midweek at home to Ross County. Former Don Joe Shaughnessy, Matthew Millar and Ryan Flynn replaced Richard Tait, Kyle McAllister and Kristian Dennis, those three all dropping to the bench.
The sides were greeted by pouring rain at Pittodrie, the Dons required to play towards the Beach End in the first half. It was the Saints who had the first opportunity, breaking quickly thanks to a precise ball out from Shaughnessy, David Bates coming across quickly to block Brophy's shot.
The Dons responded and grabbed the lead on seven minutes. A free-kick curled in from out on the right from Funso Ojo picked out Marley Watkins unmarked on the edge of the six yard box. Alnwick parried away his initial header but Watkins followed in smartly to poke the rebound over the line.
Two minutes later, it was 2-0. Lewis Ferguson bundled his way into the box, the ball eventually reaching Jay Emmanuel-Thomas. His shot was blocked, the ball squirting across the penalty area and dropping nicely for Christian Ramirez to sweep it past Alnwick on the swivel.
It should have been three on 11, an outrageous reverse pass from Emmanuel-Thomas setting Watkins away to the by-line. He pulled it back for Ryan Hedges who didn't quite get the right connection, dragging his shot across goal, but just inches in front of Ramirez, darting in at the back post.
The Buddies weren't finished though, Ross McCrorie robbed of possession out on the right by McGrath after 18 minutes. The cross came into Millar and his header looked goalbound until Bates appeared on the line to head the ball away to safety, a reminder that this game was far from done.
With the rain getting worse if anything, Saints broke the offside trap as the Dons lost the ball in midfield again, Millar chasing away at inside-right before crashing a shot goalwards, Lewis doing well to push the ball behind for a corner on 27 minutes. Brophy was replaced by Main at that point after taking a knock a few minutes earlier. The corner was driven in from Tanser on the left and Millar came flying in with a header, Lewis producing a super reflex save to drag the ball to safety, then another to block a shot at the near post.
McCrorie went on the run after winning possession in his own area, galloping pretty much the length of the field down the right on 34 minutes, only for his cross to be cleared.
Emmanuel-Thomas flicked on to Hedges who then set Watkins off to the by-line three minutes later. His pull back reached Hedges a dozen yards out, but he didn't get enough on his shot to trouble Alnwick.
The Buddies were back in it on 42 minutes, a crisp finish from Tanser just inside the box after McGrath set Millar off to. The by-line on the right. His cross found Tanser and his first time shot left Lewis with no chance tosave.
Aberdeen were having none of that though. Within 60 seconds, Watkins had restored the two goal advantage. Emmanuel-Thomas headed it on, Hedges was able to work the ball on to Watkins and he picked his spot, drilling his shot across goal and into the bottom corner.
There was time for the referee to book Jim Goodwin before the break, their conversation continuing in the tunnel, the 22 players happy to get back inside for a warming drink.
HALF-TIME: ABERDEEN 3 ST MIRREN 1
The Dons started smartly after the break and a Ramirez header from 10 yards was just wide of the post on 48 minutes, following good work down the right by Emmanuel-Thomas and Ojo.
The visitors then enjoyed a decent spell of pressure, penning Aberdeen in, but without carving out a clear opportunity. The Dons made their first change on 59 minutes, Teddy Jenks coming on for Emmanuel-Thomas to add another body in midfield.
Jenks almost made an instant impact, bursting away down the right and driving a shot across goal. Alnwick got a strong hand to it, Fraser completing the clearance within the six yard box. There were penalty claims from the corner, Fraser running into Jenks, but referee Collum wasn't interested.
Ojo was next in on the act on 66, Brown releasing Hedges. He drove into te St Mirren box before feeding Ojo, sprinting alongside him. His low shot was blocked by Alnwick who was up quickly to save the rebound from Ojo too. Millar then made way for Dennis as the Buddies looked to find a way back into things after the Dons had started to reassert control.
Hedges should have tied it up on 69 minutes, Jenks' pass putting him in with just Alnwick to beat, but the goalkeeper again kept his team in the game with a decent save as it was becoming one-way traffic now.
No matter, the fourth came two minutes later. Aberdeen surged forward down the right again, Hedges to Watkins to Jenks who dug out a fine cross through the six yard box to where Ramirez was lurking at the back stick to poke the ball home.
Ojo was in on the act on 73, joining up with the attack to fire in a drive from the edge of the box that was deflected behind, Brown heading wide from the corner before Erhahon joined the fray for Ronan on 74 minutes. Connor McLennan was Aberdeen's second change for Hedges four minutes later, Niall McGinn on for Watkins in the 83rd minute.
St Mirren had an opening on 85 with a free-kick 20 yards out, Tanser's first hit thumping into the wall, before he drilled the rebound low and hard and just wide of goal. Tanser was then the first player to be booked for a clumsy tackle on McGinn with a minute to go.