Barcelona have written a formal letter of complaint to governing body Uefa about the refereeing decisions made in the first leg of their Champions League quarter final tie against Paris Saint-Germain.
Tito Vilanova's side recorded a 2-2 draw against the Parisian side in France, but Barca have claimed referee Wolfgang Stark "did not know the rules of the game".
The Blaugrana were unhappy with what they saw as a series of mistakes from the official, including Stark's decision to allow play to continue when two Barca players were off the pitch injured.
Regulations state that play should stop in that instance, while the official also allowed Zlatan Ibrahimovic's first goal to stand when it appeared he was offside.
"Barcelona have sent a letter of protest to Uefa regarding mistakes made by the referee in the game against PSG," the Barca spokesman said.
"We just want to express our surprise that professional referees do not know the rules of the game," he added.
Blaugrana right-back Dani Alves had earlier claimed that the official had been influenced by comments from Real Madrid boss Jose Mourinho.