The Champions League holder has filed a formal complaint about the conditions at San Siro during Wednesday evening's quarterfinal against the Rossoneri.
The Catalans were held to a scoreless draw in Wednesday's encounter and players such as Xavi, Lionel Messi and Javier Mascherano, as well as head coach Pep Guardiola, stated after the match that the poor conditions made things difficult for the team.
Barcelona brought up the state of the pitch during the post-game meeting with UEFA representative Mikalai Varabyov, and the Bulgarian official has included the Blaugranas' formal complaint in his report of the game.
Varabyov has submitted his version of events to European football's governing body, and UEFA is expected to ask Milan for an explanation about the poor state of the pitch following Barca's complaint.
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