The Scotland-born, Sydney-raised 16-year-old - viewed as a star in the making by Socceroos coach Graham Arnold and green and gold great Tim Cahill - has netted three goals in four appearances for the Three Lions at U-17 level, leading to the conclusion he had already made his choice over which nation to represent.
But with father Mark and grandad Alex both former Socceroos, the temptation to follow in their footsteps appears alive and well.
Before heading to Manchester airport on Sunday to board a flight to join Gary van Egmond’s side for a friendly clash against FC Twente, Robertson told The World Game: “Spending a fair bit of my early years in Australia (from the age of four to 12), I’ve got a real connection with the country and making an appearance would definitely be an honour.
“I’m looking forward to this chance and to hopefully show a bit of what I’m about.
“It’s been a good season so far at club level - and I think my game’s been progressing pretty well (after a number of injury setbacks in recent years).”
Van Egmond is assessing the merits of a 20-plus party of players at a talent identification camp in Netherlands, with a 1-0 win over FC Utrecht’s youngsters followed by a 4-0 loss to Ajax’s young guns on Saturday in a reminder of the gap between Europe’s best and brightest and Australia’s next gen hopefuls.
Pleased to have Robertson available after a number of false starts - alongside the likes of Southampton youngster Caleb Watts - van Egmond told The World Game: “We need to balance everything off in regard to what’s happening with him from the club at perspective.
“The most important part of this is him, and ensuring the national team door is always open and we’re looking to see how we can best accommodate that.
“There’s no pressure and it’s not a matter of him signing on the dotted line (in making an unequivocal commitment to Australia).
“We’re welcoming (him) in, and like some of the others here he has opportunities with other national teams through family links.
“It’s about showing them what it’s like, being as open as possible and seeing how it all works.
“This is a training identification camp and we’ve had players from all over Europe coming in.
“In Alex’s case, you’re not at Manchester City unless you’re a good player and it will be great to see him within our environment.
“There are plenty of good players we need to find out about heading into October’s (AFC World Youth Cup) qualifiers in Uzbekistan.”
Robertson Sr, who played for Australia at the 1997 World Youth Cup, said: “From my point of view there’s a lot of pride in Alex heading off to represent Australia.
“What this shows is that there is an intent there for Alex to potentially one day represent Australia at senior level.
“I think this makes a statement that Australia is still in his heart.”
Robertson signed a four-year deal at the Etihad last year, and has been called up by Pep Guardiola to train with City’s senior stars on several occasions this season, in recognition of his promise.
City’s U-18s, for whom Robertson has been highly influential, top the league, are in the last eight of the FA Youth Cup and the final of the Premier League Youth Cup.
