The familiarisation process around Ronny Deila is still in its infancy but, already, this much can be said with some degree of confidence: their young Norwegian manager is not easily pleased.
Celtic's run of results after five friendlies and two European qualifiers reads satisfactorily: win, draw, win, draw, win, draw, win. Consistency has been hard to gauge given the contrasting strength of the opposition and even Deila's own selections. FK Krasnodar, Rapid Vienna, LASK Linz, Dukla Prague, KR Reykjavik and Dynamo Dresden amount to a humdrum half-dozen opponents while Celtic have been aiming to get fit and match sharp while progressing in the Champions League. What has been quietly revealing over the series of games has been Deila's reaction to them.
At no point as he raised his voice when commenting on Celtic's performances to the media. His composure has not slipped. But nor has he attempted to airbrush his team's limitations or gloss over their mediocre passages of play. Nothing could have been more alarming for Celtic than to have had Deila gushing with breathless enthusiasm about one display after another, sounding constantly pleased with everything. He would have looked weak and ingratiating if all he had for their performances was the propaganda of ceaseless praise. No manager comes across well when he trots out uninterrupted platitudes.
In fact, Deila's cold-eyed post-mortem of the 4-0 rout of the mediocre Icelandic champions on Tuesday night acknowledged all the shades of grey in Celtic's untroubled victory. They were 3-0 up on a part-time team after 27 minutes but did not score again until the 71st, despite pressure and chances. "In the second half we wanted to do the same things and I don't think we managed that. That is something we have to work on in the future - to get 90 minutes and to really try to destroy the opponent when we get early goals."
Every manager can talk about voraciously going for more and more goals. It goes down well with supporters. But Deila made the same pronouncements during his years in charge of Stromsgodset and his teams reflected his philosophy by establishing a reputation for a high tempo, pressing style of play. It seems like he is doing more than simply paying lip service, in other words. In the Murrayfield media room Deila spoke further about wanting his players to use "every minute on the pitch" to improve and develop as a team. "There is still a lot of work to do," he said.
After the first leg in Reykjavik - a 1-0 away win in his competitive debut as manager - he had been similarly clinical and, in some senses, unimpressed: "The first half was sleepy for me. It was sideways passing and I hate too much sideways play. We should have been more effective."
These were low key observations about minor complaints. Deila has been truly critical of his players only once so far, although it was so unexpected, and specific, that the impact was striking. Eighteen days ago the Celtic players could have had little inkling of what was coming after his second match in charge. They had drawn 1-1 with Rapid Vienna in Austria. "There was a lack of energy," said Deila. "We looked tired and we need to do something with their attitude. The body language wasn't good. I can accept not playing well but the most important thing has to be the attitude and that was lacking. You can talk about a lack of quality...but not a lack of intensity."
Deila has praised individuals and the team when he felt it was merited but he has not seemed obsequious or ingratiating when discussing Celtic's performances. There has been a healthy readiness to detach himself from his new players and tell it as he sees it. Whether he will be even more blunt after a conspicuously poor performance will be revealed in due course.
Neil Lennon was not averse to ripping into his men after their worst displays and there is every sign that Deila will do the same. There was also an echo of Lennon in another remark the new manager made after the Murrayfield fixture. "Things are happening around my players all the time," he said. It was in reference to Southampton's attempt to sign Fraser Forster. Lennon used to sound similarly exasperated about interest and speculation around Celtic players.
Clubs seem to have only two public reactions when they receive bids for their players: either the offers are accepted or they are openly dismissed as "derisory". The latter was Celtic's description of Southampton's offer for Forster. All the same, these matters have an established way of playing out. Deila naturally described Forster as part of his plans, part of Celtic's future, and so on. The club had no wish to lose its best players or break up a successful team, he said. Lennon said much the same, for what seemed like press conference after press conference last summer, about Gary Hooper and Victor Wanyama. Both left in the end.
Southampton have taken in just under £60 million since the end of the season having sold Luke Shaw, Adam Lallana and Rickie Lambert. One side starting with an unrealistically low bid, and the other ridiculing it as derisory, has never been an impediment to business eventually being done in football. The likelihood is that the phoney war will evolve into serious negotiations which more accurately reflect Southampton's enthusiasm for one of England's World Cup goalkeepers and Celtic's determination to get the going market rate if he wants to leave.
As with all managers in these circumstances, in the meantime there is only so much Deila can usefully say.