grada360.com says the raised voices of Real players and coach Jose Mourinho could be heard in the players' tunnel after the match.
Mourinho was the first to let rip.
"I'm going to press conference. I'm not going to send any of you! Since you were not able to show your face for me on the field, I will defend myself," he barked, before leaving the locker room.
Then the players kicked off.
"Come on boys, what happened to us? (...) We are Real Madrid!" declared Iker Casillas.
No-one responded, until Gonzalo Higuain replied: "We all know what happened to us, we need air. We cannot breathe."
Then Sergio Ramos piped up: "What you need to do is have more intensity. Train as you play!
"What we can't have is someone like Xabi having to run around to cover for four of you with the body he has!"
Cristiano Ronaldo was not heard during the row.
Mourinho returned to silence the stoush.
"Forget it. We'll talk about things on Wednesday, after the Champions League."