Jose Mourinho's number two says the Blaugrana are aware that they target match officials and has backed Nuri Sahin to overcome his difficult start to life in the Spanish capital
Barca stars Lionel Messi and Xavi hit out at the standard of refereeing in La Liga, prompting Jose Callejon to accuse the Blaugrana of being hypocrites.
Guardiola was quick to leap to his players' defence, but Karanka feels the Camp Nou outfit frequently complain about referees, pointing out that his side have been frequently castigated for protesting decisions.
"They know that they do complain," Karanka said, according to Marca. "Now it's them who are talking about referees."
Karanka went on to speak about Nuri Sahin's situation at the Santiago Bernabeu. The Turkey star has found first-team chances sparse during his time in the Spanish capital, but the 38-year-old has backed the former Borussia Dortmund midfielder to overcome his problems.
"He isn't at the right level of confidence because he hasn't been in shape and hasn't had opportunities.
"He came from Germany as a major player and seems to be missing that. But he'll prevail."
Finally, Karanka reiterated that Xabi Alonso will be fit to play against Getafe on Saturday, but that the local derby comes to soon for Angel Di Maria.
"Xabi has trained with us and is doing well. Di Maria is not 100 per cent yet."
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