Real Madrid forward Cristiano Ronaldo claims Barcelona get a lot of 'outside help' and has accused Javier Mascherano of 'cheating'.
The Portuguese winger was left in a foul mood following Real's UEFA Champions League exit at the hands of Barca on Tuesday night.
A 1-1 draw at Camp Nou was not enough for Jose Mourinho's men, as they crashed out of Europe's premier club competition 3-1 on aggregate.
A 2-0 defeat in the first leg of an eagerly-anticipated continental clash proved to be Real's undoing, with the fall out from a fiery encounter at Santiago Bernabeu still ongoing.
Real raised countless complaints after that encounter over what they considered to be unfair officiating.
The capital giants saw their pleas fall on deaf ears, as Uefa made it clear that no action would be taken, and their sense of injustice was heightened following their midweek trip to Catalunya.
Ronaldo believes favouritism towards Barca once again cost Real dear, with the game having been taken away from Mourinho's side before it had even begun.
"We knew we could beat Barca, but the referee didn't let us," he said.
"Once again it was the referee that didn't allow us to dictate the outcome.
"The referee in the first match (Wolfgang Stark) took away our chances of playing the final. Whoever knows anything about football knows that Barcelona get preferential treatment.
"Barcelona are a difficult team to beat because they get outside help. Next year they should give the cup directly to them."
Real's blood was boiling again on Tuesday after they saw a Gonzalo Higuain goal disallowed for an apparent foul by Ronaldo on Barca midfielder Mascherano.
Ronaldo, who was pulled up for a trip, maintains that he did nothing wrong and has questioned the tactics employed by Barca and their Argentine enforcer.
"Javier Mascherano wasn't like this at Liverpool," added the former Manchester United playmaker.
"He must have learned all these cheating tricks at Barcelona."