RONNY DEILA seems as laidback as The Fonz enjoying a cocktail in a hammock.

It is difficult to recall a time when the Celtic manager seemed as much as even a trifle perturbed, even when patiently dealing with a room full of newspapermen. If they were ever looking for an example of stereotypical Norwegian cool to front up a campaign, then Deila would be their man.

He has warmed up a bit latterly with the introduction of the Ronny Roar, a fist-pumping salute to the Celtic support after every win, even if the tribute has lost something of its spontaneity in more recent times. But Deila angry? It seems hard to imagine, even after a surprise setback like Wednesday night's defeat at home to St Johnstone.

But, yes, he reveals there have been times when he has lost his temper since becoming Celtic manager. His wrath is rarely at players making individual mistakes - that he can tolerate - but directed at those he believes are lacking in the correct attitude to their work. Celtic face a pivotal eight days as they continue their quest for a first treble in 14 years, taking on Dundee United in the William Hill Scottish Cup quarter-final then again in the League Cup semi-final next Sunday. Deila stands on the cusp of greatness and needs everyone pulling their weight accordingly.

"I am an emotional guy so that can happen [that he loses his temper]," he revealed. "I don't shout because they make mistakes. I shout if there is a bad attitude. Then I get irritated because everybody should have a good attitude. The easy things we have to do well but on the pitch people make mistakes and you never go after them. I have a longer perspective on things. Over time you have to learn from your mistakes. In one game, you can't do that. You have to give them the freedom to try."

Perhaps it is not a surprise that, as a qualified teacher, Deila likes to be hands-on with the squad. "I talk regularly with the players," he added. "If they don't have the commitment in training I will take them in and talk with them about it so that we have the same references. What is 100 per cent? What is a good attitude? This conversation is going on all the time.

"That's also to get them conscious about what they are doing because if they are not 100 per cent there could be difference causes, different answers to why it is like it is. That's how you change. Get them to commit on things and you have to follow them up all the time. Are you doing what we are saying? Are you coachable? Is it going the right way?

"But I can't teach them things if they haven't experienced it. You can tell them things but they have to experience it. What can they learn from this period? And what can they do better the next time we have so many games? It's about training, travel, everything to get things perfect so you have enough energy for every game. Every player here is very professional."

Defeat to St Johnstone was frustrating but not a huge surprise to Deila who felt the demands of the recent fixture list - two Europa League ties against Internazionale, and a high-stakes league game against Aberdeen - had taken it out of his players. The schedule is no less congested but the extra day's rest ahead of tomorrow's Scottish Cup tie could make a big difference.

"I feel I have to see a little bit behind the result. We have lost four times in the league and three of them have been when we have played a lot of games. Hamilton was the last game before we had the national team break. A little bit like now, it was three days after the Europa League when we had been home to Zagreb and the same with Inverness - that was three days after the Champions League qualification [against Maribor] and I changed a lot in the team.

"It is not the second and the third and the fourth game that is hard when you play so many games. It is the sixth and seventh game after each other and also only having three days instead of four between games. It is a big difference because you cannot get 100% rested. You lose 10% against Inter Milan and then go into the game against Aberdeen and lose another 10% again because you can't rest. You saw against St Johnstone that the first 25 minutes was good, we were controlling the game, playing quick and getting chances but suddenly it was like a click and the energy was out of the boys.

"This time it is four days' rest and that is an important thing. It is an extra day and also it is not a 12pm kick-off but 3.30pm so I am glad we play on Sunday and we are going to bounce back on Sunday - I am confident of that."