Ancelotti's job is on the line after their Champions League elimination at the quarterfinal stage.
But former Barcelona captain and coach Koeman insisted on Marca: "In the end, in football, the guilty parties are the coaches. We must recognize that Ancelotti is doing a great job. He is the coach who has won the most titles in the world.
"He is a good coach, intelligent. He manages a team like Madrid with so many stars very well.
"For me he is not the culprit. If they did not win, we must look for the responsibilities among everyone, but in the end in football the coach is always the culprit."
"No favourites for Copa final"
Koeman also spoke about the Copa del Rey final between Barcelona and Real Madrid.
He also said, "There are no favourites in finals of this type. If you analyse it, from a footballing point of view, Barcelona could have better results, but in a match between Barça and Real Madrid anything can happen.
"And for Madrid it is an opportunity to compensate for the elimination from the Champions League. They are receiving criticism for their game and their results, but in a Copa del Rey final between two big teams there are no favourites."