The los Blancos assistant lambasted the official for what he believes was a soft sending off for Angel Di Maria against Deportivo La Coruna on Saturday night
Goals from Kaka and Gonzalo Higuain overturned the host's first-half lead, but the comeback failed to lift spirits following Di Maria's dismissal for refusing to advance all of ten yards at a set-piece.
The Argentina international will therefore miss the highly anticipated Primera Division Clasico fixture next weekend, as he became the third Madrid player to have been sent off in as many league games.
"Di Maria did not do enough to be expelled," the irate Karanka told reporters after the match. "I haven't talked to him about it, but it will indeed be news when Madrid manage to finish a match with 11 players."
Turning his attention to the comeback at Riazor, the 39-year-old acknowledged his team's assured second-half performance, before singling Kaka out for special praise.
"Deportivo played well throughout the game, but our attitude in the second half was different from at the beginning," Karanka added.
"He [Kaka] played really well. His state of mind helps him and this is important for the team, that he is playing well and that he is another alternative. That is always positive.
The Brazilian playmaker confirmed the state of his progress, saying: "The team is playing well and things are getting better for me too.
"I am a lot better. What we have around the corner is exciting and it’s the decisive part of the season. If the manager wants me to play, I will be there to help in those matches."
Kaka had become a bit-part player after being dogged by form and fitness issues during his Bernabeu career, but a run of strong performances alongside fixture congestion has seen him reinstated into the line-up.