Cardiff City have offered their condolences to the family of the fan who died after being attacked outside Wembley before Tuesday night's international between England and Wales.
Police have named the 44-year-old man as Mike Dye, who was assaulted before the Euro 2012 Group G qualifying match, which England won 1-0.
Six men - all believed to be Wales supporters - are being questioned by police about the incident.
Mr Dye was found with head injuries on a concourse area outside the turnstiles at the venue at around 7.20pm on Tuesday night.
Paramedics revealed he had also suffered a heart attack before being rushed to a North London hospital.
Mr Dye was a lifelong Bluebirds fan and the club paid tribute to him in a statement on their official website from chief executive Gethin Jenkins.
The statement read: "Our thoughts and condolences go to Mike's family and friends at this devastating time.
"Mike was clearly a committed and passionate supporter of the club for many years and his passing is extremely sad to many within our community and the football family at large.
"We will remain in close contact with his family in the coming days and fully respect any wishes they may have in relation to public tributes.
"What matters most is that they are given time and space to mourn their tragic loss, while we will do all we can to offer our support and sympathies."
Tributes have been left at Cardiff City Stadium while colleagues at Cardiff Council, where Mr Dye worked in the highways department, were told about his death.
Council chief executive Jon House said: "Staff at the authority are devastated at the loss of their colleague and friend who gave almost 20 years of good service to the council in a very specialised service.
"Our thoughts are with his family at this tragic time and we will be offering support to his family and work colleagues."