The Ligue 2 champions moved above Lille into second on Sunday with a hard-fought 1-0 win over 10-man Ajaccio at the Stade Louis II, and now find themselves just four points behind leaders Paris Saint-Germain.
"We knew it would be a difficult match and so it proved to be," Ranieri told reporters. "The players kept their calm and kept the ball well.
"We tried to move the ball quickly and we needed to make the breakthrough. We managed that and so I'm happy. We were enthusiastic in our play but also reflective.
"We're back up to second place behind PSG and that's good but there's still a long way to go in the season."
Emmanuel Riviere scored Monaco's winner at the weekend.