IT may be a stretch to describe a last 32 match of Europe's secondary tournament as historic but there were enough references to the past at Celtic Park on Thursday night to produce a wave of nostalgia that almost bowled over those of a certain age.

The invocation of 1967 was poignant, inspiring and may have lessons for the future. For the uninitiated, 1967 was the year that Never Mind Quality, Feel the Width was first broadcast.

The title of this comedy programme was oddly apt at Parkhead as Celtic and inter Milan proved that thrilling matches are not the sole preserve of top-class sides. The quality was thus understandably below that of the Champions League but there was a pleasing width to Celtic.

This was direct result of the selection of Stuart Armstrong and Gary Mackay--Steven who fit snugly into the Ronny Deila template. In technique and in character they are already positive additions to Celtic.

Both could have been forgiven for shrinking ever so slightly in front of a huge Celtic crowd. They certainly admitted to pre-match nerves.

Armstrong said: "There were a lot of thoughts before the game about how I wanted to play and about how I wanted not to be overwhelmed by the occasion."

Mackay-Steven conceded, too, that he was not sure he would start, saying: "It's a great vote of confidence for me. I know the standard of player here and I knew I had to be patient."

Armstrong scored two goals in his European debut - he is claiming the second - and Mackay-Steven showed enough to suggest he will be the most potent threat on the break in the return leg at the San Siro.

It is their technical ability, their willingness to follow detailed instruction that was so crucial for Celtic. Deila demands width and Armstrong and Mackay-Steven provide that on the outside of a three in midfield. They also are keen to cut inside and so there is room for Adam Matthew and Emilio Izaguirre to make inroads down the wings. This worked to spectacular effect for Celtic's first goal on Thursday when the Welshman found the touchline and then Armstrong at the back post for a simple, effective finish.

There is still an air of innocence about the two Dundee United players, best illustrated by their reaction to the atmosphere at Parkhead. Mackay-Steven said: "It was amazing. It was everything I hoped it would be."

Armstrong said: "You'll Never Walk Alone was so noisy and after we came out of the huddle it was something I have never experienced before and something that I want a taste of over and over again."

Both Armstrong, at 22, and Mackay-Steven, 24, have limited experience but both have insatiable appetites to improve.

Even in the heady aftermath of great night for him personally, Armstrong would not be deflected from adhering to the ethos of the collective.

"It is a team game but as an attacking player you want to create goals, you want to score goals so to get myself on the scoresheet against such an established team is just an incredible feeling," he said. "I am just happy to have scored and contributed to the team."

Armstrong, too, is aware he has to improve, particularly in fitness levels. He suffered from cramp on a night that made demands of both his body and his mind.

"There might have been a psychological side to my cramping, maybe it was mentally draining. I was quite nervous before the game but as soon as it kicked off those nerves went away and I focused on the game. I blanked everything out.

"Perhaps nerves played a part in the tiredness but there was a lot of running, a lot of chasing, a lot of keeping in shape. It was a mixture of hard work and a lot of emotion."

This hard work must continue tomorrow as Celtic face a Hamilton Academical side with Aberdeen still chasing in the SPFL Premiership.

Armstrong insists there will be no emotional comedown but was prepared to look at the return leg with Inter at the San Siro, not least because it is a tie that should suit his mate, Mackay-Steven, who is not only quick on the break but makes good decisions when defences are stretched.

"I thought he was terrific against Inter in the way he runs at defenders," said Armstrong. "He had them on the back foot and he was a real threat for us going forward."

He added of a match Celtic almost certainly have to win to progress after the 3-3 draw in Glasgow: "He could be key in the San Siro. The way he plays all it takes is the perfect pass and he is away on the break. If we get one of those passes to him, he can break the lines and he has incredible pace. The way he gets away from defenders is just phenomenal. That is something we will be looking to utilise over there. "

Celtic have not given up hope of Europe beyond February. Armstrong and Mackay-Steven are already crucial to the realisation of such ambition. They supply the width, they also promise to bring the necessary quality.