Sergio Ramos was dismissed during his side's 2-0 win over Rayo Vallecano for two yellow cards, and the 39-year-old is less than impressed with some of the calls that have gone against his side this season.
"It doesn't surprise us at all," he told reporters after the match.
"We know what has happened before, and we are not surprised at all. It was bad for the match, which had started well for spectators."
Coach Jose Mourinho elected to leave Karim Benzema on the bench for the entirety of the clash, but Karanka insisted such decisions were taken for the greater good.
"These decisions are always made for the good of the team. The goal is that the people on the bench can help out," he continued.
"The team played very well, even after the red card. At first, it was very tactical, then much more physical. We are happy because we got all three points."