Ronaldo enjoyed a remarkable spell at Madrid, scoring at least 40 goals in each of his nine seasons at the club to inspire them to 15 major trophies.
However, after helping Madrid secure a third-straight Champions League triumph in May, Ronaldo felt the time was right for a new challenge.
That brought about his shock move to Juventus for a €100 million ($116m) fee, a deal which has been considered something of a coup for Italian football.
"Cristiano Ronaldo's departure for Juventus will change Italian football," Neymar told reporters.
"It will once again be the Italian football that I saw as a child.
"Cristiano is a great player, is a football legend, a genius, so we have to respect him.”
Neymar, 26, had been strongly linked with a move to Madrid as a direct replacement for Ronaldo.
However, the world's most expensive player has since reiterated his desire to remain at Paris Saint-Germain ahead of the 2018/19 campaign.