The Leicester City head coach was immediately impressed with N'Golo Kante's work-rate during their first training session together.
Kante has been the driving force behind Leicester’s stunning tilt at the title this term with his tireless running, agility, awareness and composure in possession.
Leicester’s engine has been a revelation following his summer arrival from Caen and may now end the season with a Premier League winners’ medal with just six games left to play.
The East Midlands outfit shelled out €8million on the relative unknown defensive midfielder following the departure of Esteban Cambiasso in the close season, with the move proving to be key to the Foxes’ considerable success.
Kante’s consistent performances at the King Power Stadium earned the 25-year-old his first international caps for France in March.
After coming off the bench in an away friendly against the Netherlands, he started and netted his first goal for his country in a 4-2 success over Russia at the Stade de France four days later.
Italian boss Ranieri admits he was immediately impressed with Kante’s ability from the very start of his tenure at the club.
"When I arrived for my first day of training and I saw the quality of these players, I knew how good they could be," he told The Players’ Tribune.
"This player Kante, he was running so hard that I thought he must have a pack full of batteries hidden in his shorts. He never stopped running in training.
"I had to tell him, 'Hey, N'Golo, slow down. Slow down. Don't run after the ball every time, okay?'
"He says to me, 'Yes, boss. Yes. Okay.' Ten seconds later, I look over and he's running again."