Ronaldo left Real Madrid after nine years in the summer, to sign for Juventus, which all but ended his long-term rivalry with the Argentine.
Since leaving La Liga Ronaldo has been continually asked to discuss Messi and earlier in the season set the Barca star a challenge.
The Portuguese said: “For me, life is a challenge, I like it and I like to make people happy. I would like him (Messi) to come to Italy one day. Like me, accept the challenge.”
Reacting in an interview with Marca, Messi insisted he does not need to change.
“Accepting Ronaldo’s challenge to join Italian football? I don’t need any change.
“I’m at the best team in the world. My challenges are renewed year after year. I do not need to change teams or leagues to set new goals. I am at home and I do not need to change,” he said.
