Guillermo "Guille" Fernández Casino (born 18 June 2008) is a Spanish professional footballer who plays as a midfielder for Barcelona Atlètic.
[2] In March 2022, following impressive performances for the club's Infantil A squad, he was promoted to the Cadet B team - playing with players a year older than himself - and marked his second appearance with a goal.
[3] The following year, in August 2023, he was included in Barcelona's under-18 squad, despite only being fifteen, for their pre-season preparation.
[5] Continuing his meteoric rise at Barcelona, Fernández was included in the first-team squad's training for the first time in October 2023, alongside fellow youth players Pau Cubarsí, Marc Guiu and Áron Yaakobishvili, due to the absence of a number of first-team players.
[5][6] In September 2024, Fernández was included in senior team's squad for several La Liga and UEFA Champions League games, but so far remained on the bench in all of them.