"We can fight but we are underdogs," the Italian told reporters at a Monaco Grand Prix charity match where he was 'coach' to an All Stars XI against a team of Formula One drivers and others.
"The fairytale happened once and we won. We want to defend our title of course, but for us it's very, very important to maintain the Premier League," he added.
"Our plan didn't change. OK, we won. We want to defend our title. We know it will be difficult but we don't care."
The smiling manager dodged questions about the imminent return of old rival Jose Mourinho, the manager who replaced him at Chelsea, at Manchester United after the departure this week of Louis van Gaal.
"I don't want to speak about this. Next season will be another fantastic season because (Pep) Guardiola is arriving (at Manchester City), (Antonio) Conte (at Chelsea) and Jose. It will be a very tough and good season," he said.
A year ago, former Monaco coach Ranieri turned out for the same pre-Grand Prix charity match with Prince Albert in the lineup and with his own future in question.
Dismissed in November 2014 as national coach of Greece after a shock defeat to the Faroe Islands, he was appointed by Leicester to some consternation last year.
"Something happened in one month that changed my life," he said of the final matches of the season that saw the Foxes finish 10 points clear of second place Arsenal and looking forward to a maiden campaign in the Champions League.
"I can say only thank you to my players," added Ranieri, who mingled with the small crowd and posed for selfies with spectators after the match. He had earlier posed next to a silver and blue 'King Power' throne with 'Claudio' on the back.
"I want my players to continue to have the right attitude and then I can accept all the results."
On Tuesday evening, with a team of All Stars instead of underdogs and swapping Leicester's King Power stadium for a principality, that meant also accepting defeat.
The All Stars lost 3-1 to a team that included double Formula One world champion Fernando Alonso and Red Bull's 18-year-old race winner Max Verstappen.
