Guler struck once and also laid on one of Kylian Mbappe's two goals on Sunday.
Ancelotti said afterwards: “The game seemed to be over. We had the chance to score the fourth with Güler. Then we made the change because Asencio was tired and couldn't go on. We suffered a bit more than necessary.
"You have to take into account that with Asencio coming off, we were missing six defenders and we’re not always able to fix these things. But we did very well for an hour, we could have managed the lead a little better, but in the end it was a nice win.
“Güler progression is a natural one for a player who wants to play for Madrid, who has a lot of quality, who has worked hard and has not lost his confidence. It’s clear that the Güler from September is not the Güler of today, he has changed a lot.
"His physical profile has also changed, he is much stronger and he still has the same quality. It has been a quite normal and natural progression for a young player at Real Madrid."
Pressure off Guler
He added, “I see him being much better and with less responsibility than last year. Last year he seemed to have a lot of responsibility for his age. He’s handling it well. He’s calmer and much more confident. If he makes a mistake, it's not the end of the world. A few months ago, I called out those around him and now I have to congratulate them because they’ve done very well."
Real Madrid must win at Montjuic
Real Madrid next go to Montjuic for the final El Clasico of the season against leaders Barcelona.
He also said: “If we win, we’re a point behind. LaLiga is in Barcelona's hands, but we’ll have more chances if we’re able to win. It's a great opportunity. We're going to prepare well for Sunday's game, which I'm not saying will be decisive, but almost.
“We played the last game a week ago. It was a very competitive game and we came close to winning. We don't have to invent a lot of things. We’re going to play a serious game. It's very important. We're going to play with all the confidence in the world. Despite all the difficulties, we’re there and to be able to fight this match is something nice."