Gustav Mortensen

Gustav Julius Mortensen (born 19 March 2004) is a Danish footballer who plays as a left-back for Belgian Pro League club Standard Liège.

Career Lyngby BK Mortensen is a product of Lyngby Boldklub's youth sector and fought his way up through the youth ranks. On 20 May 2021, Mortensen became the youngest debutant in the history of Lyngby - at the age of 17 years, 2 months and 1 day - when he came off the bench in a Danish Superliga game against OB on 20 May 2021. This was his only first team appearance in that season. In the upcoming 2021–22 season, where Lyngby played in the Danish 1st Division, Mortensen only made two appearances: both in the Danish Cup.

In August 2022, Mortensen signed a new contract until June 2025. Mortensen made a total of four appearances for Lyngby in the 2022–23 season.

After just five appearances (29 minutes in the league and 67 minutes in the cup), Lyngby confirmed on June 20, 2024 that Mortensen would be on loan to Danish 1st Division club Vendsyssel FF for the coming season. On July 19, 2024 he made his debut when he was in the starting lineup in the league match against FC Roskilde.

On September 8, 2024, Lyngby confirmed that Mortensen - who was on loan to Vendsyssel at the time - had signed a 1-year contract extension, so his deal now expired in June 2027. After a season that ended in relegation for Vendsyssel, it was confirmed that Mortensen would return to Lyngby following the conclusion of his loan spell.

Standard Liège On 15 January 2026, Mortensen joined Belgian Pro League club Standard Liège on a deal until June 2030.