Real again had the rub of the green for Sunday's win over Athletic Bilbao.
Karanka told Marca, "I think it's been the same story many times. When Real Madrid win, the referees are always talked about. I prefer to talk about the six game unbeaten run and that they are much more reliable than any other team in the top flight. That's why they are where they are in the table.
"The strength is that they have returned from lockdown spectacularly, maybe three or four months after the match against Manchester City, [where] there had been some doubts.
"Once again [Zinedine] Zidane has got the magic touch. Players like Sergio Ramos, [Karim] Benzema or [Thibaut] Courtois are getting back to their best. When you have quality and the squad depth of Real Madrid, it's normal that these things happen."