The Ligue 1 side have lost just once in the top flight this season and sit in third, following promotion last term.
After bringing in a number of high-profile players such as Radamel Falcao, Joao Moutinho, James Rodriguez, Eric Abidal and Ricardo Carvalho, Ranieri had expected the transition to take longer.
"It was a surprise because it's not easy to build a team in one month," Ranieri told BeIN Sport.
"But I have very, very good players."
Ranieri also explained the challenge he faced in bringing the right players to the club, rather than simply star names.
"We want to bring experienced players, champions, and also young players to do the bigger blend of experience and young players," he added.
"Monaco is a fantastic place, for this reason.
"I think that our job was at the beginning, to choose the players that want to win, want to win for them, and for the club and for the project.
"That was very important at the beginning.
"And I think Abidal wants to win, Carvalho wants to win, (Andrea) Raggi wants to win, (Jeremy) Toulalan wants to win, Falcao wants to win, Moutinho too. That is important. As is transmitting this to the young people."
Despite their strong start to the season, Monaco have not won in their last three games in all competitions, bowing out of the Coupe de la Ligue to Reims in the process.
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