Having thrown away a two-goal lead to draw with Sochaux the previous weekend, goals from Mounir Obbadi and Radamel Falcao helped the principality club to a 2-1 victory at Stade Louis II on Sunday, despite Bafetimbi Gomis' second-half response for Les Gones.
"We played well in the first half and I said to the players that we were in the same situation as against Sochaux when we were leading by two goals at half-time and that we needed to keep our focus," Ranieri told reporters. "Gomis scored a good goal but in the end we won.
"Everyone needs to keep the ball and slow the game down when necessary. Obbadi is phenomenal, a top player. Falcao worked hard for the team with his pressing and protecting the ball and people need to think a bit more about him."
Monaco are in action on Wednesday when they face Reims in the Coupe de France.