The Giallorossi currently lie two points adrift of Inter and need to win away to Parma this weekend to keep up the pressure.
Ranieri said: "I am convinced that the team has reacted well. Parma will try and beat us.
"They have the serenity of a team that has already realised its objective and tactically they will press, close down the space and attack on the counter.
"We must be very intelligent and determined. The team and the fans are one. We don't have the strength to compete with Inter, but with the help and the energy of our fans anything can happen.
"After Sunday, the letters and messages I received gave me a boost. It's wonderful to feel the warmth of the people.
"My adrenaline has now increased, no one has ever given us anything. If we fall, we get back up again. The team got 20 minutes wrong against Panathinaikos. But perhaps that defeat has given us the push to be where we are not fighting until the last with Inter."