Former Porto captain Jorge Costa has died aged 53 after having a cardiac arrest at the club's training centre, the Portuguese side has confirmed.
The defender led Porto to Champions League glory under manager Jose Mourinho in 2004 and won 50 caps for Portugal.
Costa spent a season on loan at Charlton in the Premier League in 2001-02 and retired from playing in 2006.
The centre-back moved into management and held positions at 16 clubs before taking up the role of Porto's director of professional football last season.
"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," the club said. "He left his mark on generations of fans."
It is the third unexpected death of an ex-Porto player this summer following the tragic passing of former loanee Diogo Jota and his brother Andre Silva, who spent six years at the club, in July.
Fenerbahce manager Mourinho, who managed Costa at Porto between 2002 and 2004, fought back tears and paid tribute to his former captain at a news conference before Wednesday's Champions League third-round tie against Feyenoord.
"If he could speak with me now he would say 'do your press conference, tomorrow play the game mister and win the game - forget about me'," Mourinho said.
