The Confederation of African Football (Caf) has rejected Al Ahly's request to postpone their Champions League game against Orlando Pirates on 4 August to avoid Ramadan fasting.
"The management received the rejection letter from Caf on Monday," stated the club through their official website.
Ahly football director Sayed Abdel Hafiz told Egyptian media on Sunday that the club wanted to play the game five days later to avoid the problems their players have faced since their recent Champions League tie against Zamalek.
"Our players refused to break the fast when they played Zamalek in mid-afternoon last week and are still suffering," Hafiz said.
Although footballers are permitted to break the dawn-to-dusk fast during the Muslim holy period, most refuse, with Ahly defender Ahmed Fathy recently saying they learn to adapt.
The Cairo club must also find a new venue for the Group A fixture after the military owners of the Air Defence Stadium in the capital city refused to stage it.
Ahly played neighbours Zamalek last week in the Red Sea resort of El-Gouna because of security concerns in Cairo.
The match passed without incident, with officials relenting on a spectator ban - allowing about 7,000 supporters to attend.
Egyptian authorities have suggested Aswan, a city 870 kilometres south of Cairo, could host the first visit of former African champions Orlando Pirates to the north Africa country.
"What we see on television is concerning, but I am sure Caf will make the right decision regarding the venue," Pirates coach Roger de Sa told the South African media.
Zamalek and Ahly drew 1-1 and Pirates were held 0-0 by Congo-Brazzaville visitors AC Leopards in the opening Group A matches.
The group winners and runners-up advance to the semi-finals of the lucrative competition. The champions will earn a place in the 2013 Fifa Club World Cup in Morocco in December.