Perez brought Cristiano Ronaldo to Real Madrid in the summer of 2009 for a then world-record £80million.
The Portuguese superstar went on to break most records on his way to an incredible 450 goals in 438 appearances for Los Blancos.
Ronaldo helped Real Madrid win 15 major honours during his nine years at the club, including four Champions League triumphs.
He left Real for Juventus last summer for a “new challenge”, according to Perez.
However, the president admits he never had any problems with Ronaldo during their time together at the club.
“I think he already had it quite clear that he wanted new challenges,” Perez told Spanish radio station Onda Cero.
“He used that moment to say it, but I think he’d been thinking about it for some time.
“He never created any problems during the nine years at Real Madrid, never once arriving late or anything.
“I think he’s the best player I signed for Real Madrid.
“I always had a great relationship with him.
“We never had any problems, not even over money.
“We never talked about his [tax] debt.”
Ronaldo helped Juventus win the Serie A for an eight consecutive year this season.
So has Perez spoken to the 34-year-old since he moved to the Serie A last summer?
“I don’t speak about those private matters,” he concluded.