ABERDEEN closed in on Celtic at the top of the table at the weekend.

More significantly, though, Celtic closed in on a domestic Treble, their 2-0 constructive demolition of Dundee propelling them into today's draw for the quarter-finals of the Scottish Cup.

It sealed a highly-satisfying week for manager Ronny Deila which started with success in his first ever game against Rangers to send his side into the League Cup Final, moved up a gear with the signing of Stuart Armstrong, Gary-Mackay Steven and Michael Duffy, then brought the bonus of resolution in the quest to get Kris Commons' name on a new contract.

Deila concedes, however, that the feelgood factor which all of the above generated around Celtic Park would have been allowed to haemorrhage out of the club had they come to grief at Dens Park.

Paul Hartley and his players were only too willing to take full advantage if the Bhoys - who were forced out of their hotel rooms at 2.30am on the morning of the match due to a rogue fire alarm - ended up sleepwalking into this cup tie.

The danger was that, having secured safe passage through the long-awaited and much-hyped League Cup tie against Rangers, the focus might have been lost ... along with the chance of a Treble.

But there is a resilience, awareness and determination among this group of players which was not present earlier in Deila's tenure.

The contrast between how they struggled when they first visited Dens Park this season, back in August, struggling to a 1-1 draw during a period when they were shipping points faster than Hapag Lloyd ships cargo, and how they they went about their business from the very first whistle to the last at the weekend is as stark as it is illuminating.

It's one thing for Deila and the likes of Kris Commons to speak in accord about everyone now singing from the same hymn sheet.

It's quite another to see this in action. On Saturday, it was patently clear, even for the most myopic among us.

And it's this togetherness which Deila saw in spades during training last week, and what gave him so much confidence that they were not about to fall on their sword when they faced giantkillers Dundee, the side which slayed Aberdeen in the previous round.

The goal in seven minutes from Leigh Griffiths set the tone. The second from Stefan Johansen two minutes after the break sealed the deal.

Before, during and after the goal celebrations, Celtic bossed the match, almost to the point of being bully Bhoys.

Given how they had been given the runaround by Dundee at the same venue earlier in the season, it was heartening for Deila to observe.

After six games unbeaten, Hartley bemoaned the fact his side failed to turn up for this tie.

Deila believes he knows the reason why they could not lay a glove on his side - and it had nothing to do with the Dens men being punch-drunk.

"The difference this time from the previous visit to Dens Park is completely down to us," said the Hoops boss.

"Dundee are better than we allowed them to show they were. They proved that when we met them in the summer.

"That was the worst game we played last year.

"But, you can see the development we have made since then.

"What we did on Saturday, the way we controlled the game, was something to be proud of.

"We had the tempo to do this, and we could have scored more goals than we did while denying them any more than one goal-scoring chance."

The seventh straight shut-out - Celtic last conceded when they lost 2-1 to Dundee United at Tannadice on December 21 - gives Deila as much satisfaction as the current scoring form of his side.

It's what gives him the confidence to claim he believes Celtic can now beat anyone, something which would have been considered a ludicrous call in the embryonic months of his managership of the club when stringing more than a couple of wins together before shooting themselves in the foot seemed to be their destiny.

Deila has placed so much emphasis on developing players, developing relationships and developing partnerships.

At Dens, there were copious examples of this in action, with the link-up play between Commons, Johansen and Griffiths particularly potent, like a trident piercing at the heart of the Dundee defence.

Only the enforced withdrawal of Commons at the interval, after he reported feeling a twinge in a hamstring, provided much-needed respite for the twisted-and-turned home side.

Truth be told, the 1-0 advantage at that point - Griffiths extending his fine run of form with a neatly-headed opener - should have been significantly more.

And when the over-worked Scott Bain only managed to push out another well-placed Griffiths' header from another precise Lustig cross into the path of the man-of-the-match Johansen, a more accurate reflection of Celtic's dominance was provided.

Deila was able to tick off another big game, and made no attempt to hide his pleasure, not least when he gave his three-punch salute to the fans at the end of the match.

He said: "I was very, very pleased.

"I was so proud of the boys, to come from a tough and important game against Rangers and do it one more time.

"The attitude and energy of the boys was very good.

"We looked sharp and Dundee couldn't cope with the tempo.

"I wasn't concerned that we were only one goal up at half-time.

"I saw that, if we needed to, we had another level to go up."

An ominous footnote for every other team in the land. Perhaps Inter, too.