Sir Alex Ferguson, who knows a thing or two about good players, has hailed Kieran Tierney as ‘phenomenal’ but admits Scotland have a problem.

When Arsenal signed Kieran Tierney from Celtic they were told they were getting an amazing player who would run non-stop and become a real favourite with the fans.

Although his Arsenal career was slow to start because of injury, since he got fit Tierney has shown all those words to be nothing but an underestimate.

“I do think Scotland have some very good midfield players, and I’m not sure how they’re gonna play Robertson and Tierney in the same team,” Ferguson said about what is a growing headache for his country.

“I know there were some situations where they played Tierney as the third centre-back, but the form of Tierney since he’s gone to Arsenal has been phenomenal.

“Robertson’s career at Liverpool has just got bigger and bigger.”

Tierney missed Arsenal’s dour 0-0 draw with Crystal Palace due to what was initially called ‘muscle tiredness’. It was then revealed the club feared it was worse than that and they sent him for an MRI scan which, thankfully, showed no issue.

The defender is expected to be back in the Arsenal squad for Monday night’s Premier League game against Steve Bruce’s Newcastle.