That’s from former Madrid defender Christian Panucci.
The Italian right-back ended a three-year spell in the Spanish capital, where he won La Liga and the Champions League, to move back to Serie A.
But Panucci, who also had a 10-game loan spell with Chelsea, lasted just a year with Inter Milan and has acknowledged his regret at wanting to ever leave Real.
Ronaldo is another man to swap Madrid for Italy recently having completed his €100million (£88m) switch to the Serie A champions last week.
That was after nine years at the Bernabeu where he became the club’s all-time record goalscorer and won a glittering collection of trophies including four Champions Leagues.
The 33-year-old is expected to continue his 40-goal-a-season form, which he has maintained for eight straight seasons, in Turin as they look to Ronaldo to help them end a 23-year wait for European glory.
But Panucci has warned Ronaldo that he may yet come to rue his decision to leave Real.
“When I left Madrid I was convinced,” Panucci told Spanish radio station El Partidazo de COPE.
“I wanted to leave Madrid and it was the biggest foolishness of my sports career, and I regret it now.
“Cristiano is going to win because he is too good a player not to do it. It’s normal madness for Cristiano, he’s the best in the world.
“He’s a very smart signing who is going to give other great players a push to come to Italy.
“Being a champion is in his blood.”
Panucci anticipates a difficult campaign ahead for former club Real Madrid, who have been linked with moves for Chelsea duo Thibaut Courtois and Eden Hazard after Ronaldo’s exit.
“It could be a difficult season for Madrid,” Panucci – now the manager of the Albania national team – said.
“Zidane is leaving, Cristiano is leaving. It’s not easy to substitute them and more after winning three Champions Leagues in a row.”