Real Madrid had an early lead through Brahim Diaz before Betis overran the visitors through goals from Johnny Cardoso and Isco's penalty.
At the final whistle, Roncero reviewed the game, stating: "I'm sad because Madrid has missed an opportunity to maintain its good momentum. It started like a shot and after the 20th minute it went into a state of saying 'let's go to the spa, things are going well' as if Betis were a lesser team.
"Madrid should value more what the team itself is worth. And today, so to speak, it resigned. It had a feeling of letting itself go. I can accept that the rival is better than you one day and they beat you, which is the beauty of this sport. But what I have never endured at Madrid is the feeling of letting yourself go as if nothing happens. It does happen. If we lose the league by three points, who do I complain to? Why are there players who don't rebel?
"In the last 10 minutes it attacked a bit, but how many times have we not seen Madrid really rebel, biting until the last minute... And I'm not going to pick on Güler, but today the kid didn't understand what Madrid is. Endrick came out with a different attitude. What is clear is that either Madrid has lost the bull's face in the league or it is not losing sleep over it. I have not seen any outbursts of saying 'the league is slipping away'. When you feed your enemies, it makes me feel terrible.
"Bellingham was missing, yes, he is the soul of the team, but today I am not satisfied with excuses. I hope that on Tuesday they will try to make amends to the fans and play a great game. I want to think that there will be changes for Tuesday: Valverde, Asencio, Camavinga in the starting line-up... The attitude today after the 0-1 is unacceptable."