STUART McCALL says consistency is the key for Celtic's two new Bhoys to become Scotland stars.

The national team coach has been impressed with the transition of Gary Mackay-Steven and Stuart Armstrong to life at Parkhead following their move from Tannadice.

It has led to calls by many for the pair to be recognised at international level, especially given their showings in the Europa League against Italian cracks Inter Milan.

And while McCall agrees Mackay-Steven and Armstrong have started brightly in green and white, the former Motherwell manager is looking for the pair to establish themselves in Ronny Deila's starting XI.

Speaking ahead of Scotland's friendly with Northern Ireland at Hampden later this month, McCall said: "Gary and Stuart's impact at Celtic will certainly have caught Gordon's eye.

"When we played England, all of their players were playing at the top level of the Premier League and mostly in Europe.

"The Celtic boys and Steven Naismith are playing in Europe and it definitely helps you.

"Gary and Stuart have hit the ground running and performed well in Europe, so that will be to their advantage.

"The big challenge for the two of them is to play regular for Celtic between now and the end of the season.

"You have guys like Forrest and Commons in those areas - both good players. James just needs a run as he has the ability.

"But Gary and Stuart couldn't have started any better. Their confidence will be high and it's a bonus for the Scotland squad that they have gone there and got the experience of European football.

He added: "It's big leap because you have to win every game as the pressure is higher. Even if you get what you believe is a decent draw, it's not.

"From our point of view, it's pleasing they have settled so well but the big test is to stay in that team for a long spell."