Mackay-Steven said: “The manager was angry but mainly at our performance. We were in the driving seat and in the second half we didn’t create enough chances to win the game. The manager was frustrated at losing goals from set-pieces as we have worked on it a lot. I don’t know whether the wind was a factor. The ball travelled a long way. We will need to look at it on the video and eradicate any mistakes.”
The Bhoys lost 2-1 at Pittodrie, with some questionable defending leading to both goals.
The equaliser came from a penalty given away by Dedryk Boyata, whilst the winning goal - at which time Aberdeen were down to 10 men - came from a long free-kick.
It was the winning goal which truly would have frustrated Deila, as the free-kick was one in a position which should not have led to a goalscoring chance.
It was simply punted into the box, and thanks to some static defending from the Celtic back-line, Paul Quinn found it easy to tap the ball over the line.
Goalkeeper Craig Gordon looked to have little command over his box, and there appeared to be no chemistry between the stopper and the defensive unit in front of him.
Last season, Deila proved himself a strong defensive coach, and he has every right to be frustrated with the lack of quality shown by the Bhoys in the loss at Pittodrie.
The 2-1 defeat was not the only game this season in which Celtic have failed to defend with any sense of top class quality, and Deila needs to start sorting his players out if he is to relive the slight pressure that is growing on his job.