Jose Mourinho broke down in tears as he paid a touching tribute to Jorge Costa following his shock death.
Costa passed away at the age of 53 after suffering a cardiac arrest at Porto's training centre on Tuesday.
The former defender, who was serving as the club's director of football, was rushed to hospital but could not be saved.
A club statement read: "Throughout his life, both on and off the pitch, Jorge Costa embodied the values that define FC Porto: dedication, leadership, passion and an unshakeable spirit of conquest. He left his mark on generations of fans and became a symbol of Portismo."
Costa made 383 appearances for Porto and famously captained them to Champions League glory in 2004 under Mourinho.
Speaking ahead of Fenerbahce's Champions League qualifier against Feyenoord on Wednesday, Mourinho was asked about Costa as he fought back tears during an emotional press conference.
"It's part of my history that goes," a tearful Mourinho said, before reflecting on his leadership qualities.
"You have captains and you have leaders. It's not always about the armband but what you represent. And Jorge was one of these guys who cleaned the garbage and let the coach do his job as a coach.
"That's perfection for a coach when his captain does this work. Of course, I'm very sad it's part of my history that goes."
Jorge Costa passed away at the age of 53. Image: Getty He added: "But let's forget football, let's focus on him, on Jorge, on his kids, who I met when they were really kids, but now are grown men.
"And I'm here now because if he could speak with me now he would tell me, come on, do your press conference. And he would say tomorrow play the game Mister, win the game and forget about me. That would be Jorge.
"So that's what I'm going to try and do, do my job today, do my job tomorrow and then cry after. But today and tomorrow I have a job to do and I know Jorge would tell me to do my job."
Costa won 24 trophies during his legendary spell at Porto, including the aforementioned Champions League, the UEFA Cup and eight Primeira Liga titles.
He ended his playing career away from the club but returned last year as director of football.