UEFA's control and disciplinary body will on Wednesday morning hear Legia's appeal against the governing body's decision to award Celtic a 3-0 second-leg victory following the Polish champions' registration error.
Legia saw a 6-1 aggregate victory turned into an away-goals defeat after bringing on Bartosz Bereszynski in the belief that he had served a three-match ban - only to discover they had not registered him in their squad for the previous round.
A statement from Legia read: "Football is our common passion. We are deeply convinced this beautiful game should be based on universal values - shared by everyone who enters the pitch to compete for victory. Those values, widely accepted by the entire European football family, are: football first, fair play and respect.
"Over previous days we have been closely following the decisions of European football authorities. We believe the most crucial element of the game is the result settled in honest and fair competition on the pitch, as highlighted in the UEFA values: "Football First"!
"We are responsible for the fate of the game and we should all feel obliged to protect the beautiful football heritage based on these superior values for the generations to come.
"We all hope that all decisions made over the next days and forever after will respect the spirit of the game that begins and ends on the pitch. Join us if you support football united around the idea of fair play, respect and sports competition."
UEFA applied rules on ineligible players to award the game by forfeit to Celtic, with the 3-0 win taking the Scottish champions through on away goals.
The decision was made little over an hour before the draw for the play-off round, which paired Celtic with Slovenian side Maribor, while Legia were handed a Europa League tie in Kazakhstan.
Legia stated that the decision was made "under pressure of time and circumstances" and expressed hope that the appeal body consider the mitigating circumstances and use its powers to impose a less strict sanction or withdraw it altogether.
Celtic have said little on the matter other than that they were disappointed with Legia's appeal to the club's traditions on Sunday.
And manager Ronny Deila is focusing on a trip to Slovenia next Wednesday.
Deila said: "It is an appeal and we have to see what comes out of it. I am a football trainer not a politician.
"We are preparing to play Maribor."