Raphael Varane has told L'Equipe that the struggles he had at Real Madrid during Carlo Ancelotti's management pushed him to become a better player.
Varane will play against his former boss, now at Bayern Munich, in the Champions League quarterfinal next month.
The France international struggled to convince Ancelotti he was worthy of a place in the starting lineup and said: "Since he left, I've improved.
"I could have perhaps played more under him if I could have shown him he could count on me in difficult times.
"There was less turnover and you really needed to bring the house down to have any chance of playing again. I wasn't able to do that."
Varane said Ancelotti had "made his choices, and I can understand them" and added: "I didn't play as much as I would have wanted, but it pushed me to ask questions of myself and progress."
After his former mentor Zinedine Zidane took charge of the first team midway through last season, Varane again struggled to establish himself as a regular starter.
He said that had been "difficult for me to go through" and added: "At that time, I would have liked to have had more of an explanation.
"We have had disagreements, but we're both capable of admitting when we're wrong. Since, we get on very well.
"I needed to know what I had to do to get time on the pitch. He told me things clearly, notably that he considered me important.
"We set out again on a good footing. I try to return the trust he has in me when he plays me."
France international Varane will now talk to Madrid about extending his contract, which expires in 2020.
"I asked myself whether the club was in sync with my project, that is to say playing," he said.
"The president and the coach confirmed they had the same line of thinking. I'm good in Madrid. All the lights are green."