Christiano Ronaldo is one player that has excelled in top three leagues in Europe. For instance, he spent 12 years in Spanish league and won two LA liga and 4 champions league. Despite all this feat, he thinks that the Italian league is the most difficult in the world. 
He told Dazn: “I’ve adapted to the Italian League and it’s a difficult League, the most difficult one for me and for all forwards.
“It’s the most difficult league for me, it’s full of quality players. I didn’t expect this much quality in the Italian League, they’re very good.
“It’s harder to score in the Italian League than in the Spanish League.
“The Spanish League is more open, the teams risk more. Here, not so much. Here, the team’s priority is to defend first, and then to attack.
“That’s not true for Spain. Spanish games are more open. Always, with most teams.
“I don’t miss Spain or Portugal, it is what it is. Obviously, I left many friends and a great team behind, a team that made me feel loved, people, friends.
“But I don’t miss the country, I have the same things here. It wasn’t really difficult for me.”