The trainer lauded the pair of substitutes as being decisive to the Paris side's result, but admitted he was concerned with an injury to new signing Lucas Moura
Benjamin Moukandjo silenced Parc des Princes as he handed the visitors a shock opener, but an inspired brace from Zlatan Ibrahimovic put the home side back in charge.
And Ancelotti was quick to credit the win to his substitutes' contributions.
"The first period was similar to those [defeats] against Reims and Sochaux, as we had problems in terms of intensity and motivation," the 53-year-old stated to InfoSport.
"However, the second-half reaction was good. Menez and Gemeiro brought intensity. Menez was not ready to play 90 minutes, so I saved him for the second half. Gemeiro was useful when he came on too, as he always is.
"We did not play good football in this game, but it was important to win. Now we have more time to prepare for our next game [against Saint-Etienne]."
However, Brazilian star Lucas Moura was forced off before the hour mark and Ancelotti has revealed his concern over the injury.
"He must pass tests. Am I worried? Naturally," the Italian said.
"I hope he will recover soon, but I cannot say as I have not yet spoken to the doctor."