The Portuguese superstar has enjoyed an outstanding debut season in Turin, scoring 23 goals in 34 appearances across all competitions.
Ahead of the heavyweight last-eight clash, Cruyff has compared Ronaldo to his late father Johan, who enjoyed a legendary career as a player and coach at both Ajax and Barcelona.
Ronaldo hit a stunning hat-trick in the last 16 against Atletico Madrid to help Juve progress in dramatic style and he is chasing a fourth consecutive European Cup after a trio of recent successes at Real Madrid.
"In football, there are so many mortals and very few immortals: I can say that, like my father, Cristiano will always be remembered," Cruyff told Gazzetta dello Sport.
"Along with Messi, without having to say who is the best. Many have had a great year but only they had 15 great ones."
Juventus will fancy their chances of going all the way to the final if they can overcome a formidable Ajax side this month, with the first leg set to take place in Amsterdam on Wednesday night.
The youthful Dutch outfit are currently top of their domestic league and are chasing their first Champions League triumph since 1995, when they beat AC Milan before losing to Juventus in the final the following year.
Cruyff has been impressed by the team's progress this term under Erik ten Hag, expressing his joy that the club have rediscovered their identity on and off the pitch since the home stadium was renamed as the Johan Cruyff Arena last year.
"The stadium bears his name and the philosophy of play and life is now in the DNA of the club," Jordi added. "This Ajax plays the football that my father would have loved.
"Young, happy, daring, attacking. In Amsterdam, it never changed. This generation has more talent than others and always controls the ball. It is a pleasure for the eyes to see them play."
Cruyff also assessed the challenge Juventus pose Ajax in the last eight, insisting that Italian football has evolved in recent years.
"Juventus? Italian football has changed," said the 45-year-old. "Now Italians score and play a lot more. The mirror is Buffon: over the years he has had to use his feet much more. Certainly, at Juve, there is always a good defensive organisation but they also know how to create."