Goals in either half from Niall McGinn and Sam Cosgrove looked scant reward for the Dons on a night when they had 33 goal attempts, 14 of them on target, only to concede one with virtually the last kick of the ball.
Lucus Lingman threaded a ball in behind a defence that had hardly been troubled all night and substitute Tommi Jantti showed real composure to guide the ball behind a disbelieving new Aberdeen captain Joe Lewis.
Not that the goalkeeper was alone in that feeling as the 41 travelling RoPS supporters were the only ones in the 14,377 crowd not to be shocked by what they had just witnessed – and the trip to the tiny Keskuskenita Stadium next week will now be a lot more tricky than it should have been.
That late-late strike certainly spoiled what was shaping to be a perfect day for manager Derek McInnes who signed a two-year contract extension prior to kick-off, but only two of the players he handed deals to in the summer started this Europa League 1st round qualifier.
Atlanta United’s versatile on-loan player Jon Gallagher looked bright and sharp in a free role while Wales international winger Ryan Hedges impressed with his pace and link-up play, particularly when Aberdeen finally broke the deadlock after 36 frustrating minutes.
Of course for all the changes McInnes has made since taking over it somehow seemed appropriate that someone initially signed by predecessor Craig Brown should be the decisive figure.
McGinn, pictured, was initially ruled out of the tie after surgery to repair ankle damage at the end of last season but the ever reliable Northern Ireland international was in his usual place and usual form.
Aberdeen started by spraying the ball around at pace but came up against former Inverness Caley Thistle and Ross County goalkeeper Antonio Reguero on top form on his return to Scotland. Someone who lost four goals at Pittodrie on a previous visit with the Staggies might have conceded as many in the first half had the Spaniard not made wonderful saves to deny Hedges, Sam Cosgrove and Lewis Ferguson during that busy spell.
He enjoyed a major let-off when last season’s 21-goal striker Cosgrove completely miscued in front of goal from just eight yards out but McGinn was never going to be so careless.
Instead the irrepressible winger gathered an incisive Hedges pass with his back to goal as well as defender Kalle Katz and, in one sweet sweeping motion, spun clear before clipping an exquisite shot from a tight angle into the far corner of the net.
That was his sixth European goal for the club, and his first since scoring against Fola Esch three years ago, but a reunion with that side from Luxembourg in the next round is unlikely as they lost at home to Georgia’s Chikhura Sachkhere last night.
Any doubt that Aberdeen would be there seemed to be eased at the start of the second half when Cosgrove made amends for his first half howler by deflecting Gallagher’s cross into the net.
Reguero didn’t look too clever at that point but his form prevented his team returning to Finland on the back of a real hammering as he made further saves from McGinn, Hedges and Cosgrove.
The team third bottom of their division had looked neat and tidy in possession in the first half without ever causing much of a threat on the counterattack, and Aberdeen’s superiority was all too evident the longer the game went on, until that stunning finale.