IT was 5.25pm on a Saturday.

Or as the new Caledonian calendar now dictates it must be described: Year Zero plus 20 minutes after the Scottish League Cup final draw had been made at 5.05pm.

Ronny Deila, the Celtic manager, bounded into the media room, and declared: "I don't want any questions about Rangers, okay?"

Oh, how we laughed. It is better, one supposes, to get all that humour out of the way before one concentrates for the best part of three months on a football match that will consume, at most, just more than two hours of action.

Deila, though, has reason to be light-hearted. In Year Zero plus one, it may be more instructive to consider the Norwegian's recent past than to ponder the intricacies of a match that is some way, and one transfer window, in the future.

Celtic's 1-0 victory over Inverness Caledonian Thistle was their fifth consecutive win. This run followed a 1-0 defeat by Hamilton Academical that was wretched in terms of the champions' ability to create chances and to overwhelm a side that had just been promoted. It climaxed when Scott Brown, the team captain, accused players of "hiding".

The bombast of a Celtic-Rangers semi-final rings in the ears but they should not dismiss the echoes of those whispers that circulated around Celtic Park in the aftermath of Ali Crawford's winner on October 5.

Would Deila last the season? Was the club simply too big for him? Were the players buying into his methods?

The manager and the team have answered these, at least for the moment, in the only possible way. They have won matches: 5-0 against Ross County, and 2-1 over FC Astra in the Europa League, 2-0 and 1-0 over Kilmarnock and Inverness respectively in the SPFL, and 6-0 over Partick Thistle in the League Cup. This is the arithmetic that bolsters managers and gives players a confidence in his methods: five victories, 16 goals scored, one conceded and progress made in three competitions.

The victory over Inverness was marked by a nervous finish, an inevitable consequence of Celtic scorning chances to increase their lead, legs becoming tired after a draining period of games and the introduction by John Hughes of Aaron Doran and Billy McKay as the Inverness manager sought to profit from an increasing vulnerability on the part of the home side. Lukasz Zaluska, introduced as Craig Gordon was allowed time to recover from a minor knee injury, made good saves from McKay and Carl Tremarco and the Hughes strategy came up pointless.

The narrowness of the margin of victory, though, will be a concern for Deila. Celtic, playing in his preferred 4-3-3 set-up, created openings but failed to capitalise.

It was not as if Dean Brill had one of those days that goalkeepers can reserve for big matches under siege. It was rather that Celtic, by touch and hesitation, simply failed to put shots in on goal from good positions.

Their goal came when Scott Brown, typically active and strong in regaining possession, robbed Danny Williams and set up a breakaway that John Guidetti gilded with a decisive strike.

"I was definitely fouled but the referee ended up saying he gave us the advantage. I don't know how we had any advantage from that, because Celtic just went up the park and got their goal from it," Williams said of Craig Thomson's ruling.

"It was clearly a bad decision. It just looked like a stonewall foul to us. A lot of our lads stopped when the foul was made and the decision has punished us in the end."

It was this immobility that annoyed Hughes, who was otherwise entitled to be pleased with the performance of his side. The absence of Richie Foran and the drought endured by McKay have had a negative impact on Inverness but they have enduring strengths in those such as Graeme Shinnie, Greg Tansey and Ross Draper that make them a side of substance.

Williams, who played in the loss to Rangers in the League Cup this season, said: "Celtic are in a league of their own'.

This has not yet been franked by a lead in the table but Deila has cause for satisfaction. The defence looks stronger with Van Dijk and Jason Denayer forming a good partnership, Mikael Lustig and Adam Matthews are fit, Brown is made for regaining possession even if he has an inbuilt capacity to lose it, and Guidetti is scoring goals.

He now enters a period in which Celtic could make progress in Europe, advance in the Scottish Cup and reach the top of the league.

There are, of course, threats to these ambitions this month in the shape of Aberdeen and Dundee in the league and Astra and Salzburg in Europe, with a Scottish Cup opponent - with Rangers as much a possibility as any other side - to be named today.

In Year Zero plus one day, the focus is on a Hampden semi-final next year, but Deila has much to occupy his thoughts in the meantime, including the following reflection.

The Celtic manager described Inverness on Saturday as "the best team we have played against so far in the Scottish league". Rangers beat them 1-0 at Ibrox in September.