There was a point not much more than 12 months ago when Neil Lennon was lamenting his fate as Celtic manager.

“I don’t think I’m going to get the chance to build the type of team I want to see here,” he said.

Lennon felt that time was running out on him. At that point, back in the early winter of 2011, Rangers looked like they were streaking ahead in the title race, while Lennon’s Celtic were toiling.

And, as much as the Celtic fans loved him, the catcalls were beginning to ring in his ears around Celtic Park.

It is instructive to think back to some of the chatter among fans and the media in those months. Lennon, it was felt, wasn’t working out. Ally McCoist, himself an untried manager at Rangers, appeared to be getting the better of him. It looked like Lennon would be binned – he felt it himself.

Now look where we are. Lennon has performed a minor miracle – Celtic have actually beaten the modern, dazzling Barcelona – and his team are in the last 16 of the Champions League. The fact that some are even tipping Lennon and Celtic to reach the last eight is a remarkable state of affairs.

Lennon has confounded just about everyone – including me. He was deemed too young, too raw, too impetuous for the Celtic job. It was said he created unwanted tabloid headlines.

I remember one seasoned Scottish football observer saying: “Celtic have made a grave mistake in handing the manager’s job to Neil Lennon – he is too callow and he lacks discipline.”

Lennon is a bloke I like a lot, but I created a minor tension between us by writing a column which cast doubt on the wisdom of the club giving him the job back in May 2010.

I thought Celtic was too big a club for him - or for anyone - going into his first managerial job. In fact, the logic of that argument still doesn’t seem so flawed.

But Lennon is succeeding at Celtic where older, more experienced coaches might have failed. He has done so by an ability to learn lessons as he goes along, by an intelligent understanding of football, but also through a strength of character.

The last point probably cannot be overestimated. I’m not talking about any of the off-field lunacy he has had to deal with. Rather, one of Lennon’s strengths as a player was his ability not to be fazed or overawed by anything.

For instance, when Lennon and Celtic went away to play teams as prestigious as Juventus and Bayern Munich under Martin O’Neill in the Champions League, it scarcely entered Lennon’s head that he might look inferior on the pitch.

On the contrary, he believed he could square up to anybody.

It will be lost on no-one that, in five years in Glasgow, O’Neill never once took Celtic to the Champions League’s last 16 in three attempts, while Lennon has done it after his first taste of the group stage.

Gordon Strachan managed it twice after O’Neill left, and now Lennon has added to these feats. The fact is, as vulnerable and headstrong as we all believed Lennon to be, he now stands comfortably beside these two figures in Celtic’s recent history, while still only being 41.

It is by no means a scene of flawless progress. Celtic have stumbled in the SPL and, thus far, Lennon has failed to find an answer to that.

There have also been recurring, key moments when a Celtic team has faltered under him: against Ross County and Kilmarnock at Hampden; fatally against Inverness Caledonian Thistle in April 2011; and even against Arbroath last week.

On all of these occasions against inferior opponents, Lennon has looked nonplussed, unable to explain where it went wrong.

But today, having guided Celtic astutely through this Champions League group stage, Lennon looks a figure of substance. He has talked convincingly about his plans throughout this European campaign so far. He also has a deep “feel” for Celtic and what the club requires, which is no handicap.

Neil Lennon is some way off from entering the pantheon – and he might never make it. Right now, though, his stock is rising.