The Real Madrid defender was dismissed during his side's 2-0 win over Rayo on Saturday, and suggested his reputation may have preceded him
The Spain international received two yellow cards withing minutes of one another after scoring his side's second goal, and felt guilty about letting down his teammates.
"I am hurt by the situation," he was quoted as saying by AS.
"It is not normal for me to be sent off within two minutes. I'm not one to come in with hard tackles or to do something evil. It's easy to send off Sergio Ramos. It's worrying.
"It hurts me to have left my teammates disadvantaged and to have forced changes. Spanish football deserves the best referees because we have the biggest players.
"Referees are required to interpret situations. My first card was completely unfair. You cannot leave a team with 10 men for that."