The Italian was encouraged by his side's balance in attack and defence and believes the club's young players are beginning to show encouraging signs of progress
Cristiano Ronaldo, Karim Benzema, Gareth Bale, Isco and Alvaro Morata all struck to give los Blancos their fourth consecutive Liga victory, but Ancelotti was particularly impressed with the defensive balance within the side offered by the two Spanish midfielders.
"I think it was a good game. It was important not to concede goals, and the whole team played well together," the coach told reporters after the match.
"It's important to have a template that the players have no difficulty playing with each other. Illarramendi and Xabi [Alonso] played very well. The team was balanced thanks to these two.
"We only lost a little control in the last 15 minutes of the first half when we played a bit slower, but those are small details. Today was a different game and I think we should be happy."
Illarramendi and Isco returned to the fold following Sami Khedira's season-ending injury while Jese Rodriguez, Casemiro and Alvaro Morata impressed in second-half cameos.
And Ancelotti was generous in his praise of the side's youngsters, adding: "Illarramendi has worked well for two weeks and was in good condition like Isco, who also worked well.
"Our young players have a lot of quality. Casemiro can replace Khedira in the line-up because they share similar charactheristics.
"They are young and will show that they are ready to play for Real Madrid."