THE remarkable revival that Scotland enjoyed during their Russia 2018 qualifying campaign was due in no small part to Gordon Strachan promoting so many of the Celtic side who were sweeping all before them domestically to his team.

Replacing David Marshall with Craig Gordon, calling up Stuart Armstrong to play alongside his club mate and captain Scott Brown and finally bowing to public pressure and giving Leigh Griffiths his chance to start up front proved transformational.

Long-suffering Tartan Army footsoldiers were left, after costly results against Lithuania, Slovakia and England, wailing “what took you so long?”

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However, it will have taken Strachan’s successor Alex McLeish far less time – try less than an hour – to determine what a difference Brendan Rodgers’s men can make to his side’s cause.

The criticism of McLeish following the 1-0 defeat to Costa Rica at Hampden on Friday evening overlooked the fact that he had, correctly in the circumstances, used the exercise to try out a new formation and blood untried players.

The dearth of right-sided options meant he was quite right to field a three-man back line even if it did not quite go according to plan and contributed to Scotland conceding the only goal of the 90 minutes.

He was, too, correct, to hand starts to Scott McKenna, who has impressed for Aberdeen this term, Tom Cairney and Kevin McDonald, who are playing consistently well together for Fulham in the English Championship, as well as Scott McTominay, the Manchester United sensation, in midfield and Oliver McBurnie of Barnsley up front.

McLeish will have learned a great deal about each of those individuals and the others he selected which will prove invaluable when competitive football resumes in the Nations League in September.

Nevertheless, the difference that Stuart Armstrong, who has played less than 45 minutes of football this year due to the hernia operation he underwent in January, and Callum McGregor, who has blown hot and cold in recent months, when they came on midway through the second-half on Friday evening was undeniable.

It would be no surprise to see the two midfielders along with their Parkhead club mates Jack Hendry and James Forrest in the starting line-up for the game against Hungary here in Budapest tomorrow evening.

It is unlikely that many Celtic players will be involved on the end-of-season trip to Peru and Mexico given that they will, in all likelihood, have important Champions League qualifiers to play in mid-July.

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But Armstrong, Forrest, Gordon and Griffiths, if they can get themselves fit and back playing as well as McGregor and Tierney, who has missed this double header with a calf strain, look certain to be major players for McLeish going forward.

They may not, despite reaching the last 32 of the Europa League, retaining the Betfred Cup, establishing a comfortable lead in the Ladbrokes Premiership and reaching the semi-finals of the William Hill Scottish Cup, have scaled the same heights as they did in the 2016/17 season.

But their Scottish contingent – minus, of course, Scott Brown, 
who has decided to retire from international football – should still make up the nucleus of the national team on the evidence of Friday night.

“When we’re at home at Hampden we have to be on the front foot the way we were in the second half,” said McLeish. “There was a huge difference in the way we played after the break.”

“The Celtic boys came on and helped us. But the change in our approach started at the beginning of the second half. We were much more positive and that’s the kind of tempo I like my teams to play with.”

Upping the tempo that his side played with, bringing in younger players with pace, helped Scotland to beat Slovenia, draw with England and defeat Lithuania, Malta and Slovakia towards the end of their Russia 2018 qualifying campaign and McLeish will need to retain that if he is to be successful in the Nations League or reach Euro 2020.

And what of the criticism of the poor display and disappointing result? McLeish has left his more experienced players, Christophe Berra, Darren Fletcher, Robert Snodgrass among them, out of the squad for these two matches. So he is refusing to be too despondent about his experimental line-up losing to opponents who have qualified for their fourth World Cup finals in five attempts and reached the quarter-finals in Brazil last time around.

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“We played against a team that’s been together for about four years,” said McLeish. “They are a team who were No.1 in a World Cup group containing Italy, Uruguay and England. So they were a decent team but we gave them too much respect in the first half.

“If I sounded a bit down then I was only trying to be measured and calculated. I just don’t like losing games. But I have to manage my own expectations along with those of everyone else.”

He added: “I’m not down, I’m calm. I don’t want to get too excited or too negative. But I don’t like getting beat. Winning football games is my reason for living. That’s part of my whole make-up so you’re never going to see me being happy after a defeat. I especially wanted to get off to a really good start, but sometimes the first pancake is never the best one.”