Leyton Orient manager Justin Edinburgh has died aged 49 after suffering a cardiac arrest.
He was taken to hospital on Monday, two days after attending the Champions League final between his former club Tottenham and Liverpool.
Leyton Orient announced his death in a statement on Saturday.
“We are completely heartbroken by this tragedy,” said Orient chairman Nigel Travis.
“All our thoughts and love are with the Edinburgh family and we know from the messages that have flooded into the club over the last week that the wider football world will share our sentiments.”
Edinburgh had just guided Orient to promotion back to the Football League after taking over in November 2017 as the club began an extensive rebuild.
“The success that Justin brought to Leyton Orient was incredible, but more importantly the impact he had on us all as a winner and a wonderful, inspirational human being will be his legacy and will stay with us forever,” said Travis.
Fans gathered at the Breyer Group Stadium on Sunday morning to pay tribute to Edinburgh.
Messages of condolence, flowers and shirts have been left and Leyton Orient have said the stadium will be open between 11am and 3pm to allow fans to pay their respects.
Edinburgh began his playing career at Southend, winning promotion from the fourth tier, before joining Tottenham in 1990.
He made 215 appearances for the club and was part of their FA Cup and League Cup-winning teams in 1991 and 1999 respectively.