Real got back to winning ways after two consecutive defeats against Barcelona and Sevilla, crushing city neighbours Vallecano with an excellent performance.
Cristiano Ronaldo opened the scoring after 15 minutes before four second-half goals, including two from Gareth Bale, made sure of the points for Ancelotti's men.
The capital club remain three points behind leaders Atletico Madrid and two adrift of fellow title rivals Barca, who both claimed victories, despite the result.
And Real's fans were keen to voice their frustration at the last two defeats, jeering a number of players including Ronaldo, a reaction that drew the ire of Ancelotti.
"I have said many times I understand when the crowd whistled us because we had deserved it. But not at the moment," Ancelotti said.
"It is true we haven't performed at our best in the last two games, however I think overall the players are doing a great effort.
"We have to carry on and we need everyone's help. And then to whistle Cristiano Ronaldo is not that understandable.
"Naturally this win is important. We reacted well. After two defeats, we have played a good match. We showed a good attitude. Moreover, we can now prepare properly for the next game.
"I do not think many things have changed. As I said before we have made mistakes in defence in the last two games, against Barcelona and Sevilla.
"Today (Saturday) we have done well. Also because we have used the counterattack and even when the team wasn't very balanced, our four defenders have performed well."
