His open, expansive, indulgent interviews have already proved that.
More importantly, he is a man OF his word. The Celtic boss promised fans that it would be attack, attack, attack, from his team, especially at home.
Any note of caution attemp-ting to creep into the psyche of his side would have the door slammed firmly in its face.
His reasoning was simple. He declared he has the better players and the support of a tremendous fanbase demanding to be entertained and see winning football.
All the boxes were ticked for Celtic in their first home game of this SPFL Premiership season to ensure Fergus McCann's unfurling of the 2013-14 championship flag was not the point at which a day of celebration started to go downhill.
Deila was as delighted as he was relieved to deliver in his first match at the stadium he can now proudly call home.
The manner of the 6-1 win - with his team hurtling out of the blocks to take the lead inside four minutes through new Bhoy Jason Denayer - confirmed that rhetoric is not Deila's vocabulary.
The Norwegian said: "I am always honest when talking in the media. I have to be me and I have to do my thing. This attacking football is what I believe in and what I have done before."
Deila's message is clearly getting through, not only to those spectating but to those charged with ensuring that his instructions are carried out.
The manager was not happy with his side's performance in the 3-0 win in their opening league match at Perth because how his team plays is just as important to the Hoops boss as how successful they are.
Just like St Johnstone last midweek, Dundee United contributed to their own downfall on Saturday with some horrendously naive defending, particularly at set-pieces.
Denayer, Kris Commons, Charlie Mulgrew and Joe Inge Berget all capitalised on that, while Berget grabbed another and Stefan Johansen punished more slack United defending to get on the scoresheet.
But Saturday's performance had much more edge to it than the stumbling Celtic display at McDiarmid Park, and made for a heartening sight with Wed-nesday's crunch encounter in Maribor looming large.
"Against United, the players were fantastic together as a unit," purred Deila. "That's important because it is about team play."
The collective pat on the back his players received was quickly followed by a reminder this is only the beginning.
There is along way to go, both in terms of fixtures and the improvement demanded.
Deila is not a man to rest on any laurels. As soon as Saturday's final whistle sounded, his mind moved immediately to how he can make his side play even better in Slovenia.
ONE negative invading the space being filled by positive thoughts generated by a 100 per cent start to their league campaign is the expected absence of James Forrest after he succumbed to yet another hamstring injury.
The explosive attacker's cameo appearance for the last 21 minutes of the game, with Celts cruising to victory, ended with him bursting forward to play the ball through for the final goal, then immediately pulling up, clutching the back of his left thigh. Boss Deila was already looking anxiously towards Forrest as Berget got on the end of Beram Kayal's low cross to make it 6-1.
Given the importance of the young Scot's dynamism and counter-attacking threat to the way Deila wants to play, it would only be natural if the manager was left asking himself why he had allowed the fragile jewel to take to the field and expose himself to the risk of another injury at such a crucial stage of the season.
But, as has been proved before, such injuries can occur just as easily on the training pitch, and Deila needed to see what condition Forrest was in to assess how much of a part he could play in Slovenia.
Unfortunately, the answer is now almost certainly none, and his team's pace will have to be provided from another pair of legs and lungs.
Berget's first two goals for the club increased his chances of filling one of Celtic's wide positions on Wednesday.
The Norwegian midfielder grew into the game, linking up well with his team-mates with clever flicks and passes.
There is still much work to be done on the defensive side of his game, however. That is something that will no doubt be given a much sterner test against Maribor.
United should have provided the perfect gauge of where Celtic stand as a team but their performance was so poor the 6-1 scoreline could be regarded as something of a false positive.
While Deila was pleased with how his side created and converted chances, and by the debut of the impressive Denayer alongside Virgil van Dijk, he was not fooled into believing they have made a quantum leap from how they played in previous games so far this season.
There will be much tougher examinations to come for them, starting on Wednesday, even though Maribor did not have as good a prep game as the Hoops, losing 3-1 away to Celje in their league game on Saturday.
DEILA will already have received detailed reports and studied a DVD of that match, given that his appetite for work is matched only by his lust for detail.
The same level of analysis will go into his own team's performance at the weekend. The Parkhead manager said: "There are still a lot of things to improve. That will always be the case.
"However, I think things are getting quicker now, and we are getting better and quicker reactions.
"The players are getting a good response to what they are doing, and that makes it easier to do it more."
There is no denying that the 44,000 fans who welcomed the team - and Fergus - back to Celtic Park, appreciated all that they saw.
The transition from how the team was asked to play as it won the last three championships under Neil Lennon to how Deila wants them to defend the Premiership flag in future will be an evolution, not a revolution.
The process of change will be nurtured by success but stunted by defeats.
Which is why the vital two Champions League play-off ties against Maribor - which sandwich next Saturday's meeting with surprise league leaders Caledonian Thistle in Inverness - will be pivotal in the new manager's bedding-in process.