Real have stumbled in the opening games of the LaLiga season.
And Ancelotti concedes: "There is enough preparation time because we are used to playing with this schedule and solving problems as we have had before.
"Being worried is not a bad feeling, it means you are dealing with the problem you have. We have had a problem in the last few games, we have not had a compact block, we have to improve it with better collective work. We all agree on this. The players think the same. When the problem is clear it is quite simple to solve it.
"It's not too complicated. We have to defend better and it's a commitment and a collective attitude. We have to work together to defend better and win the ball back. The statistics say that we haven't conceded a lot of goals: two goals in five games.
"But the feeling is that the opposing teams play too much between the lines. It's something we have to solve and we're going to do it."
Barcelona are now seven points ahead of Real Madrid at the top of the table, but Ancelotti says: "It's a small thing, what has affected us the most is that we haven't been able to play at our best.
"The season is very long. We're obviously not happy, but not because we're four points (now seven) down, but because we haven't played well."