Lionel Messi and Cristiano Ronaldo are the biggest superstars in football today. Both are incredibly talented in their own specific ways, and their statistics and trophies show that they're really, really good.
But because Messi plays for Barcelona and Ronaldo plays for Real Madrid, the rivalry between the clubs was naturally transferred to the two superstars, and someone is always looking for Ronaldo to trash-talk Messi, and vice-versa. They don't, they never really did and they probably never will, and Ronaldo reassured that position again in an interview this week:
"There is a big mutual respect between myself and Messi. The media like to make out like we have this big rivalry, but we don't. It is not like we are good friends, but there is a mutual respect on both sides."
That's the honest truth. They're not friends, which is natural, but they respect each other a lot, which is even more natural. They are rivals in the sense that they always fight to be better than the other, but it's never personal. And that's why this rivalry is so fun: both do their talking on the pitch.