There was a postcard moment when the sun shone on Dens Park and Stuart Armstrong wheeled away to celebrate Celtic’s second of the day. Dundee scored a peach of their own as they threatened to rain on the visitors' parade, but it was Brendan Rodgers’ side who left with a smile on their face.

In many ways it is Armstrong who has become something of a poster boy for this Celtic team. The midfielder, on the outside looking in when the season first began, has become pivotal to the way in which Celtic go about their business.

He has scored 12 now this season from the middle of the park, eclipsing the tally of last season when no-one other than Leigh Griffiths hit double figures for the Parkhead side.

How he fits into Gordon Strachan’s side this week remains to be seen, but he has done enough not to just win Rodgers over but to be one of the lynchpins of the Hoops midfield.

Armstrong’s workrate, his willingness to take on board the lessons handed out and his ability to get into goalscoring opportunities – as well as create them for those around him – has teased out the potential shown in his Tannadice days.

The frustration of playing out on the flank last term has been forgotten as he has flourished in the central pastures.

Rodgers has preached a relentlessness to his Celtic players, not just in terms of results – and just four points dropped in the entirety of this league campaign underlines how well his mantra has been heard – but also expects his squad to keep working, keep testing the boundaries of their own ability.

And if there is one players who encapsulates that drive for self-improvement it is Armstrong.

“His running ability, his power, he just has this inbuilt brain for scoring goals, and all different types of goal,” said Rodgers after the game. “The second goal he finished off a move where we had about five or six players in the box, lining up to score. He’s a big talent and he’s only going one way, which is nice for Celtic and for Scotland.”

And the Hoops boss believes that the midfielder is capable of making an immediate impact with the national side.

“There are obviously good players there with Scotland in that part of the field,” said the Celtic manager. “I have always believed that international football is about technique, speed, mobility and a tactical awareness of the game, to play it at a high level. And those elements of the game he has.

“He has naturally good technique. We have tried to play the game a different away this season which hopefully he has benefited from tactically, and his speed and mobility are there to see. So he has all the tools to play at the top level of international football in a really quick game. So he could certainly go in and play.”

Armstrong was key to the win against Dundee in what was a relatively subdued performance from Celtic. James Forrest could consider that he too made a decent contribution to a victory that takes the Parkhead side within just three points of their sixth successive title.

It had been an unlikely source that had given Celtic the lead from what was a relatively turgid opening period, when Jozo Simunovic sent the Hoops into break with a tentative lead.

Dedryck Boyata had had a header cleared off the line by Paul McGowan, but from the resultant corner, Rodgers’ side punctured Dundee’s resistance when the Croatian’s scissor-kicked took a deflection off of Kevin Gomis before curling into the net.

The first was all that Celtic needed to supplement the massive amounts of possession they had in the opening half, but the second was the goal that came straight from the training ground.

It was a move that began with goalkeeper Craig Gordon and brought in Mikael Lustig, Moussa Dembele, Callum McGregor and Forrest before Armstrong glanced his header into the net, and had Rodgers applauding from the sidelines.

“It’s a perfect example of a goalkeeper being able to use his feet and you saw Craig’s joy from scoring it, right the way through the team, and then we had real comfort in the game,” said the Celtic boss. “We should have added to that. And then we lost our positioning a little bit on the field and that allowed them to then go and score a goal.”

A fine strike it was too.

Substitute Faissal El Bakhtaoui cracked a 25-yard effort that almost burst the back of Gordon’s net and ensured a more nervous finale to the game than Celtic would have expected.

In between times, though, there were moments of note. January signings Eboue Kouassi was introduced to the fray and although he managed to earn himself a booking, there was little other impact from the 19-year-old.

Celtic brought on Erik Sviatchenko in the latter stages as Celtic saw the game out and protected the points.

A party awaits now at Tynecastle, a circulatory journey from where Rodgers took charge of his first league game for Celtic this season.