Ismaily, Egypt's third-most successful club, want rivals Ahly stripped of the 2009 Premier League title following a corruption scandal that has engulfed world governing body FIFA over the past nine days.
Ahly defeated Ismaily 1-0 in a rare playoff six years ago to win the title, concluding the only exciting league race of the past decade and depriving their bitter foes of their first triumph since 2002.
Ismaily came within touching distance of the title on the final day after Ahly had scored two late goals to defeat El-Geish and force a decider, but in the end Ahly prevailed, thanks to a brilliant header from Angolan striker Flavio Amado.
FIFA was shocked last month by the announcement of a US investigation into allegedly widespread financial wrongdoing stretching back more than two decades.
The Swiss authorities also mounted their own criminal probe into the awarding of the 2018 and 2022 World Cups to Russia and Qatar respectively.
"Ismaily demand an investigation into the 2009 league competition because of FIFA's corruption," the club, who were the first Egyptian side to win the African Champions League in 1969, said in a statement on their official website.
"The main reason for our loss was an illegitimate Ahly goal that was allowed to stand by the referee in their last league match against Geish … and we also want to know who was responsible for appointing a hardly known Spanish referee for the playoff.
"This Spanish referee also disallowed a goal by [midfielder] Mohamed Hommos against Ahly.
"After the recent discovery of the FIFA corruption saga, we will send a fax to the Egyptian Football Association to demand that we be awarded the 2009 title.
"If our demand is not met, we will file a complaint with the Court of Arbitration for Sport," the club, which did not clarify how their loss against Ahly could be linked to FIFA's corruption, added.
Ismaily have always maintained that Ahly receive favourable treatment from referees. Their supporters are also enraged by what they call the Red Devils' attempts to snap up Ismaily's best players.
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