Carlo Ancelotti says coaching Zinedine Zidane at Juventus changed his ideas on how to play football.
Ancelotti was in charge of the Bianconeri from 1999 to 2001 but was unable to deliver silverware beyond the Intertoto Cup despite boasting a talented squad that included Zidane, Alessandro Del Piero, Edgar Davids and Filippo Inzaghi.
However, his time with the 1998 Ballon d'Or winner helped to shape his coaching style for the remainder of a hugely successful career.
"Zidane is the first player who gave me the possibility to change the system and play in a different way," Ancelotti, now Everton boss, told Sky Sports.
"So, when I had Zidane, in the first year at Juventus, I played with a system of 3-4-1-2, having Del Piero and Inzaghi up front and Zidane a little bit behind.
"The second year, I played with a back four but keeping two strikers in front and one number 10, like Zidane.
"Zidane changed my idea about football. I was so focused before Juventus on 4-4-2 and after with Zidane, I changed, I wanted to put him in the best position for him, to let him be more comfortable on the pitch.
"The experience at Juventus was good in my opinion because I understood really well how the club has to work for the manager, so the club gave to me a lot of support in this. It doesn't matter if they fired me at the end of the second year, until the last day in Juventus, I understood how the club has to work for the manager, to support them, to help them in front of the players, to give the manager the power that he needs to manage the players."
Zidane went on to become Ancelotti's assistant at Real Madrid, where they ended Los Blancos' 12-year wait to be crowned champions of Europe by defeating Atletico Madrid after extra time in the 2014 Champions League final.
Ancelotti's time in Turin helped him deliver success at the Santiago Bernabeu and learn how best to utilise the abilities of Cristiano Ronaldo and now club captain Sergio Ramos.
"The team had some problems in the past years when I arrived there," he said. "The fact that they were not able to win the Champions League for 12 years was like an obsession for them because Real Madrid was used to winning a lot of Champions Leagues.
"You don't have to build a team around Cristiano Ronaldo and as I said with Zidane, you have to put them in the more comfortable way on the pitch. I don't think you have to build strict tactics with this player defensively because there are players who are more involved in the attacking phase and there are players who have to be involved more in the defensive phase.
"Of course, they have to work together because the team is the most important part of the game, but strikers like Ronaldo who are able to score every single game, you don't have to give too much information defensively.
"It is the easiest way to be a manager, to manage a fantastic player because they are professional, they are serious, they have personality, they are motivated, so it is the easiest way.
"Sergio Ramos also has a fantastic quality. I think his best quality he has is not tactically, it's not technically, it's character and the personality that he has and the ability he has to motivate the people around him, like his teammates. Ramos during that period was important for this, he was always at the top when the game was important and in the key moment of the games."