In an emotional farewell message, Paul Onuachu thanked his former Genk teammates and club supporters.
Onuachu left the Limburgers on deadline day for the Premier League club Southampton.
Southampton paid €18 million to secure the services of the forward.
Following his arrival from Danish club FC Midtylland in 2019, the Nigeria international ended his four-year association with Genk.
The 28-year-old was a cult hero during his time at the Cegeka Arena.
The striker scored 84 goals in 134 matches for the Smurfs.
“I want to thank everyone in Krc Genk. The board members, the previous coaches and the present coaches, staff, medical team, players, my Danish family and of course the Genkie fans that have helped me achieve and grow, not just as football player but also as a person,” Onuachu wrote on his Instagram page.