Lucas was an important member of the Reds squad around the time Alexander-Arnold started to gain a taste of life in first-team football in the 2015-16 and 2016-17 seasons.
Even back then, the Academy product was displaying some of the qualities that saw him become a Champions League winner and Ballon d'Or nominee at the tender age of 21.
Speaking on LFCTV's Legends in Lockdown show, Lucas said: "Well, I remember a few moments of Trent. I remember he came with us to play in a friendly game and I think he was 16. He was very shy and Brendan [Rodgers] was in charge.