But no amount of condemnation from others could make the Norwegian feel any worse than he instinctively does in the aftermath of damaging defeats.
“It’s as though the police are standing outside your door in the morning, waiting to take you in because you’ve done something criminal,” said a reflective Deila yesterday.
“That’s how it feels and that’s how it has been throughout my football career. Many times I have sat after games and thought ‘I don’t want to do this anymore’. Because it is so painful to lose.”
Deila was making specific reference to the League Cup semi-final loss at the hands of Ross County at Hampden a fortnight ago which preceded the 2-1 Premiership defeat at Aberdeen, ending his ambitions of a domestic treble and raising fresh doubts over Celtic’s title defence.
The 3-1 reversal to the Dingwall side proved especially painful for Deila as it came on a weekend when his twin daughters, Thale and Live, made a rare trip to Scotland to spend some time with their father. His reaction to the result at Hampden underlined the personal cost of professional setbacks for a football manager.
“The kids said a good thing to me about that,” added Deila. “It wasn’t easy to try and even look at them after that game.
“Then they said to me ‘we know how it is daddy – we talk together, but you don’t listen’. That’s what it is like when you come home from a loss. You are still thinking about the game and you are not actually there. You feel the pain twice, but that’s how it is and that is what I have chosen. I chose this life. I’ve done it for 20 years. It’s hell or heaven all of the time. That’s how football is.
“That’s why I have to try to deal with it, but if you don’t feel pain or happiness, then I think I would be very bored.
“You don’t want to wake up at times after losing. You just lie there. Sometimes you don’t sleep, you just lie there thinking.
“But that’s why I am here. Because I really care and want to turn things around. The hardest part in life is when you don’t know what the answer is. But when you know the way forward, you can do that. For me, it takes 48 hours to get the disappointment and reflection out of the body.
“I know the players have the same feeling. You can see in training that everyone is very switched on and knows what we are playing for.
“Sometimes when you are a coach or a leader, you think it is only yourself who cares. But I can assure you that the players are feeling the same as me. That is a good thing.
“Now we are very concrete in what we need to do to get good performances and results. That is the main thing.
“Are the players angry? I think they’re calm. Anger is not the thing. You have to sit down, talk together and find solutions. That’s what we have been doing. It’s been intense. But to get out of this situation you must stay calm and keep believing in what you do. Everyone has to drag in the same direction and bounce back.
“Two weeks ago, before the semi-final, we were very positive and the team were playing very well. We have also had spots in the games we have lost that were good. So we have to take those positive things and try and do better in other areas.”
Celtic face their League Cup conquerors again tomorrow when Ross County visit Glasgow on league business but Deila insists vengeance is not his primary motivation. “Revenge is a bad word,” he said. “Yes, we have something to prove and something to bounce back from. We have to take something from the first 12 minutes against them at Hampden, the way we played before we got the red card (for Efe Ambrose). If we can play like that for 90 minutes, then we can cause Ross County problems.”
Deila expects influential playmaker Kris Commons, sidelined for the past month by illness and injury, to return to action tomorrow. But he has moved to temper expectations among supporters of an instant first-team impact for on-loan Manchester City winger Patrick Roberts. The 19-year-old attracted rave reviews for his first outing with Celtic’s under-20 side, scoring once and providing three assists in a 4-0 win over Motherwell last week.
However, the teenager City signed from Fulham for £12 million will have to wait a while longer to feature in Deila’s side. “It is an 18-month loan and he needs time to adapt to how we train and play,” said Deila. “He also had some injuries before he arrived, so he still needs to get better fitness-wise.
“He was up and down in that under-20 game but did some things at a fantastic level. I’m not saying he can’t be involved in the first team but we have to use his first half-year with us to get him adapted. Hopefully, he can kick on as quickly as possible.”