Benzema made it two goals in as many games at the start of the new Primera Division campaign by scoring at Los Carmenes to seal a 1-0 triumph for Los Blancos, earning them a second win following the 2-1 opening-weekend victory over Real Betis.
Ancelotti had insisted at his pre-match press conference that there was still room for Benzema despite his desire to move Cristiano Ronaldo into a more central position, and the former Lyon striker needed only 10 minutes to again make his point on Monday.
"Karim is playing well, scoring and working hard. He's started La Liga well," the Italian said on Real's official website.
Summer signing Isco, scorer of the late winner in the lacklustre triumph over Betis, went close to doubling Madrid's advantage in the 62nd minute when he cut inside on the left and whipped in a shot which was touched by Granada goalkeeper Roberto onto the base of the post.
Mesut Ozil and Ronaldo also had openings to add to the scoring but there were no further goals, leaving Ancelotti to accept the margin of victory was not as comfortable as he would have liked.
"I think we attacked a lot but we didn't finish off those chances, which we need to do," he said. "The start of the game was good, but then our pace dropped.
"(We're) working to improve. We are trying to change the team's philosophy and at the moment the important thing is to win points.
"The first half was good and all we needed to do was score the second goal, but 0-1 is not easy to control and experiencing some difficulty is normal.
"Now what's important is the result. The team was compact and they all played well and made an effort, so I'm happy."
He continued: "We had good balance (in midfield) because (Luka) Modric and Isco played well. Isco had to make sacrifices because he is an attacking player but he played well. (Angel) Di Maria's work was impressive and he gave the team balance."
Diego Lopez was again selected ahead of Spain captain Iker Casillas between the posts, with Ancelotti reasoning: "He played the first game and the second. He's playing well - that's all there is to it."
Referee Javier Estrada Fernandez turned down two Granada penalty appeals, firstly for a handball claim against Alvaro Arbeloa and secondly when Diego Buonanotte went down under a challenge from fellow substitute Casemiro in the closing stages.
"I don't like to comment but I think the TV images clearly show it wasn't a penalty," Ancelotti said of the Buonanotte incident. "The referee had a good match."