He said: "One player doesn't make a team and certainly doesn't make a league. There are many exceptional players in the Premier League.
"Ronaldo is one of the best players in the world, if not the best. I've enjoyed watching him play, but I'm sure Manchester United will keep going strong and they now have a lot of money to spend.
"Deals like this are one-offs and exceptionally rare. The jury is out on whether they are good for the game or not, but Real Madrid have got themselves into trouble from time to time and we will have to wait and see.
"They are one of the greatest clubs in the world, but they have this system where the person who says he will spend the most money becomes the next president."