Rayo lost 1-0 on Monday night through a Robert Lewandowski penalty.
Afterwards, Perez was pushed about the match officials' performance, but was keen to avoid controversy.
Refereeing:
"As a coach, I will always try to stay out of the referee's decisions. Some days it favors us, others it penalises us. I empathise a lot with them and I will not cross that line."
Penalty controversy:
"If I say yes or no, the headline comes out on its own. I will not comment on any refereeing situation."
Match:
"At the beginning, one only feels bitter about the defeat. After that phase, we always enter into a process of analysing what happened. It is likely that with the passage of time, I will find many things that leave me satisfied with the game. One is hurt and we cannot be happy when we lose. You cannot get sidetracked by a good performance, after this we will surely find virtues to maintain for the rest of the season."
Ratiu:
"Andrei is having a very complete season both offensively and defensively. Today I had the player who demands the most from you defensively in LaLiga, Raphinha, who is capable of playing inside and outside. The test was whether I was able to support him and then be able to give us that offensive potential that he has. He started off a little bit scared, we paid a little for it. Then, the team, like him, found the feeling that you could play against these players."
Positive things:
"On the defensive side we always try to be an aggressive team so that teams like Barca that have so many offensive mechanisms and such mechanized positions, we are interested in generating chaos in the pressure so that they do not feel comfortable. We have achieved this at different heights of the field. You have to have personality with the ball, we have done many things well. We must reiterate the good things."
Getting around the rival's defence:
"We train based on the analysis of the rival. From the extracts we get, we try to generate exercises so that today when they come across it, it will be familiar to them. We have been good except for some mistakes. What we have done in training has had an effect."
Pedri:
"One of the things we've taken into account this week is that he doesn't get into the game as much. If he does, we should know what passing patterns he usually uses and that they should be controlled. I'm a coach who likes good footballers and he is one. He's showing this offensive phase, what I like about him is how he marks the ground and that spreads to the rest. It's been a joy to watch him play, except today."