Some analysis surrounding Aberdeen's recent upturn was whether it is sustainable to grind out results by relying on their defence and hope to pinch a goal.
That was turned on its head, though, as they found a cutting edge while shipping goals at the other end.
Fans must have feared the worst when Topi Keskinen struck a post and Adil Aouchiche and Kevin Nisbet both missed gilt-edged chances in the first half.
However, Aberdeen found their shooting boots after the break, finding the target with eight of their 18 shots as they dominated and pushed St Mirren back.
That came at a cost though, as Stephen Robinson's team were able to create multiple chances of their own, scoring their three goals from an expected goals value of 1.86.
Thelin must find a balance if Aberdeen are going to force their way into the top six.
St Mirren's struggles have become far more than a blip and their League Cup semi-final triumph against Motherwell appears something of an anomaly.
They were perhaps unfortunate to have a first-half Scott Tanser goal disallowed for a perceived foul on Mitov.
But they desperately need some momentum and confidence before they return to Hampden to face Celtic in the final on 14 December.