Polvara is a player Aberdeen fans have been desperate to see more of since Jimmy Thelin took charge at the start of last season.
They were robbed of that chance mostly due to injuries last term, and this season so far the manager has kept him out of the starting side.
But here he showed why there is clamour for him to play. His size, dribbling ability and knack of scoring big goals came to the fore as he provided a brilliant out ball for Aberdeen as they attacked 10 men, constantly making runs into the box.
His left-footed, first-time finish while on the turn was magnificent and sparked a side who had until then looked unconvincing in front of goal.
If he is fit, Polvara surely has to start the return leg next week.
Credit, too, to Sokler who has also been out of the picture in this nascent campaign.
The Slovenian has never shown himself to be a clinical player at Pittodrie, but he is excellent in the air and never stops running.
The pair of them - and Leighton Clarkson's control in midfield - helped change the complexion of the tie, and bail out their colleagues at the back.
Aberdeen's vulnerability is a long-running theme and needs fixing urgently. Molloy did not look comfortable at left-back and was culpable for both goals.
But he was not the only one who looked unconvincing. The team's shape when they lose the ball is still wide open and will keep standing in the way of progress unless resolved.