Get the latest Celtic news sent straight to your inbox with our daily newsletter Charlie Mulgrew raised his eyebrows as he saw a fearless 17-year-old charging into tackles at Celtic's Lennoxtown base.
And his first impression of Kieran Tierney on his maiden training session with the Hoops first team was: "Fair play, wee man." The left-back rose to prominence in Brendan Rodgers' all-conquering side before a club record-shattering £25m move to Arsenal in 2019.
But when he began mixing it with the big boys Mulgrew was still a Parkhead player, before his move south to Blackburn Rovers in 2016.
Now back in the Scottish Premiership at Dundee United, Mulgrew told the Scottish Sun : "People talk about KT's attitude now he's an Arsenal player.
Read more on dailyrecord.co.uk