The Norwegian’s position as manager has come under fresh scrutiny in the wake of the 2-1 home defeat by Molde which left the Scottish champions at the bottom of Europa League Group A.
Deila remains unfazed by speculation surrounding his position, repeating his confidence the club’s board will afford him a similar amount of time to his predecessor Neil Lennon to make a positive impact on the continental stage.
But the 40-year-old also made no attempt to disguise his dismay at the performance of his team as they slumped to the ninth defeat of his 24 European games in charge so far.
Deila confirmed he had lambasted the players in the dressing room, sparing only 18-year-old left-back Kieran Tierney from his ire. In a scathing assessment of the others who faced Molde, Deila claimed they lacked “determination, desire, character and leadership” during a match in which they were yet again fatally undermined by lamentable defending.
“I was angry and disappointed in the dressing room, very disappointed,” said Deila. “It is a lack of determination.
“That is something that Scotland is known for, it is what KT [Tierney] showed on the pitch. That’s real Scottish play, real Scottish mentality, when you go back 20 years and think of those players.”
Thumping a fist into an open hand, the animated Deila added: “F***ing like this! That’s what we need. We need more coming with the attitude KT had, because that was brilliant.
“That’s exactly what I told them – how an 18-year-old boy had shown the desire we need. That’s the bottom line, that’s something we need more of.
“If we get that into the team along with the offensive play we have, then we can do it. People have to develop these things, it is possible. Of course, some are born with more of it than others. But you are not a football player if you can’t defend – it’s as simple as that.
“Not everyone can be very tight all the time but you have to find your way to defend a goal.
“The players didn’t say anything back to me – I think they quite agree. This is about individual things and we need to get some character, leadership and determination. But you can’t threaten people to be better.”
Celtic will still qualify for the knockout stage of the Europa League if they can find a way to win their two remaining Group A fixtures, at home to Ajax on 26 November and away to Fenerbahce two weeks later.
Even if that seemingly unlikely target is not achieved, however, Deila fully expects to be at the helm for a third attempt at Champions League qualification next summer.
“This club has shown before that they stand by their managers when they have a hard time in Europe,” he said. “That is what I want and expect to get as well. I am very confident that we are going to turn it around and get improvements into the two last games of this group, which is one thing, but also into next year too.”
While Deila believes two wins in the final two Group A games is possible, Nir Bitton, sent off in the second half against Molde to leave him suspended for the visit of Ajax along with fellow midfielder Stefan Johansen, is less optimistic.
The Israel international claimed Celtic were once again punished for repeating mistakes on the European stage.
“I think we make a lot of mistakes, we make the same mistakes every game in Europe,” he said. “Teams who play us create too many chances against us. When you play in the Scottish league sometimes you don’t get punished for that but you get punished in Europe. It is disappointing.
“When you lose two games against Molde, with all due respect, you can’t think of winning against Ajax and Fenerbahce. But if we have the smallest chance to go through we will try do everything we can. You never know what can happen in football and we will see.”