Thursday night in Glasgow promises to be a big moment in the career of Ronny Deila.

Celtic versus Inter Milan, even in that ugly duckling called the Europa League, is a fixture redolent with nostalgia and glories past, and those of us in the Scottish media have quite rightly gone to town on it.

What a thrilling home-and-away draw this is for Celtic fans. It also promises to be a fresh measure of their manager.

At 39, Deila is still young and inexperienced as a coach, certainly in relation to Roberto Mancini, his opposite number in the Inter camp. If Deila does come good, he should have years and years ahead of him in football.

This is why Thursday, in one aspect, is so appealing. What will it tell us about Deila? What plan can he hatch? Can he rouse his players to make a game of it against Inter Milan?

This Celtic coach has not been without his critics. I have seen him being described as "hopeless", "inept" and "out of his depth" in the eight months since he arrived at Celtic from Stromsgodset.

Deila was undermined from the very start, when it had been perfectly obvious Celtic had been chasing Roy Keane and others. He arrived in Glasgow to a warm welcome from the Celtic support, but also to plenty sceptics who were armed with pens and laptops.

The leap Deila made from his tiny club in Norway to Celtic was huge. It only further fuelled the cynicism towards him. And then, when his team were horsed 1-4 and 0-2 by Legia Warsaw, only to be redeemed by the Bartosz Bereszynski affair, still more came the view that Deila had been a dire mistake by Celtic.

Well, here we are in mid-February. And I notice the "Deila's a dud" brigade have gone mighty quiet. Celtic are top of the Premiership - at last - and sit on eight successive wins.

A League Cup final looms against Dundee United in four weeks' time, and Inter Milan are in town this week. It has been eventful, but Deila has done a quiet, solid job in gradually muzzling his critics.

Europe is an intriguing testing ground for him. And he has had some wretched moments there with Celtic, and not just against Legia.

The dire botch that Deila and his players made in losing at home to Maribor last August in the Champions League qualifier will live long in the memory.

Yes, a new manager, a new club, and all of that. But what a botch. What a fist he and Celtic made of that night.

The next fortnight, here in Glasgow and then in San Siro, should tell us some more about Deila and his growing conviction as a coach. His team is now playing with panache, and with a mental belief in their dugout leader, but all of this has been confined within Scotland.

Let's see what happens when Deila enters the European arena again. Let's see the lessons he has learned from some scolding episodes there in recent times.

Let's see if it is true, as someone at Celtic said to me recently, that "the great thing about Ronny Deila is that he is open-minded and is able to learn and implement things."

That sounded quite a decent compliment to me. I eagerly await some more evidence of it against Inter in these weeks ahead.

Right now I admire the way Deila doesn't hang about. In Gary Mackay-Steven and Stuart Armstrong, his two new recruits, he hasn't dithered or "slowly bedded them in" in the old managerial way.

On the contrary, Deila has chucked both straight into the mix, and fashioned his Celtic team around them. There is something bold and instant in Deila which can be refreshing.

This Norwegian manager of Celtic is still a long way off from touching the coat-tails of some of his great predecessors. The pitfalls remain, and much evidence is yet to be stacked up - good or bad - before we can make a sound Deila judgement.

But he has self-belief. He shows conviction. He doesn't seem to lose his nerve. And there is a growing momentum around Deila now at Celtic which appears to augur well.

So bring on Inter. Let's see more of what Deila is about.