Southern produced a dominant display against Lee Man to be crowned 2025 Sapling Cup champions after a 4-0 win at the Mong Kok Stadium on Thursday.
The victory earned Southern their second trophy in the club's history.
It was a repeat of the final of two years ago, when Southern prevailed 2-0 against the same opponents.
Southern opened the scoring in the 25th minute through midfielder Jonatan Acosta, before goals from Stefan Pereira and Kessi Isac secured a comfortable 3-0 lead at the break.
Sohgo Ichikawa upped Southern's advantage in the 67th minute to seal the victory.
Lee Man were not without their chances, but they failed to create any meaningful opportunities with shots hitting the bar and post several times.
The Sapling Cup, which was founded in 2015, allows younger players to gain more experience at the top level.