The disappointment of their Europa League slip-up lingers but Joe Lewis knows Aberdeen cannot let it trickle into their league form.
A 2-0 defeat to Rijeka in Croatia on Thursday means the Dons face an uphill task to keep their European run going beyond the third qualifying round.
However, they still have league business to contend with.
After the 5-0 thumping of Chikhura Sachkhere last week, there was a noticeable dip in energy levels at times against Hearts before the home side ran out 3-2 winners.
St Mirren have not enjoyed the best start to the season, losing on penalties to East Kilbride in the Betfred Cup and conceding late on against Hibernian a week ago.
Lewis said: “It is important we keep our league run going. We need to keep that positivity and we can’t beat ourselves up too much over Thursday. We are disappointed and we need to come back out and show what a good team we are.
“We will have a look at St Mirren. They will be difficult opposition. It is difficult to have so many games and so many different types of games early but hopefully we have the squad to cope that can adapt and help us play in different styles to get past each obstacle.
“The next one is St Mirren and we know they have a new manager and a number of new players but we have to go there and try to stamp our authority on the game.”
Thursday night marked the first game defender Scott McKenna played since handing in his transfer request nearly a week ago.
Manager Derek McInnes spoke passionately in defence of the Scotland cap earlier this week, criticising the timing of offers from Queens Park Rangers and Sheffield Wednesday for the 22-year-old on the eve of the Rijeka game.
However, his performance in Croatia showed little sign of the speculation affecting his game, something which greatly impressed Lewis.
Lewis said: “You would never have known with the way Scott played. Scott’s attitude is one of his main positives. Things don’t affect him and I think you could see that with his performance in Rijeka – he can be proud of the way he played. I am amazed there hasn’t been a lot more interest in Scott. For me, as a defender he is one of the best I have played with.
“There is no doubt there will be loads of interest in Scott going forward. He is a great lad and a complete a professional. I have spoken to Scott about the situation but that conversation will remain in-house. He doesn’t need me to tell him how to act. He is a sensible lad and he will do what is best for him to take his career to the next level.”
It is going to take one of the Dons’ best performances in European football of late to ensure they get to the play-off round of the Europa League for the first time.
A three-goal swing is the minimum margin McInnes’ side need to achieve on home turf. Given their home performances so far have yielded 10 goals in their favour and three wins, it is easy to see why they are not counting themselves out just yet.
He added: “We felt the game was going well for us but the penalty changed that and gave them a real lift. The second goal was a killer. Yes, it is disappointing but it is half-time and we take them back to Pittodrie next Wednesday. “If we can create a good atmosphere there and we can get the first goal then I think that would give us a real momentum going forward, especially with the crowd behind us.
“I felt we played well and 2-0 was a harsh scoreline on us. We need to make sure when we get them back to Pittodrie we need to make sure we put on a performance that can get us the result we need to get through the tie.”