Legia Warsaw boss Henning Berg has revealed that his side will appeal against their Champions League expulsion after being thrown out of the competition.
Bereszynski was believed to have served his three-match suspension after missing two games against St Patrick's Athletic as well as the first leg against Celtic in Warsaw. However, the player was not included on the squad list submitted to UEFA for the St Patrick's games.
"For UEFA to make a decision like this, with all the consequences, it's unbelievable," Berg is quoted as saying by Sky Sports News.
"We acted in good faith. We made a mistake in administration with the papers for the St Patrick's games. We knew he was suspended and he didn't play in those two games or the first game against Celtic.
"We've been open and it's just a little small technical mistake in the administration, and the consequences for us now is that we are not able to play in the Champions League which was a dream for all our players and the club. It's very, very difficult to take and I think it goes against every intention of fair play and fair competition."
Celtic will go up against Slovenian champions Maribor in the Champions League playoff round.