European Cup winner Crerand told the Daily Mail: "If I am honest, I never thought I would see another player like George Best in my lifetime. I was wrong.
"Young Cristiano has many things in common with dear George: he is two-footed, lightning quick, good in the air and as brave as a lion. And - just like George - he is a good-looking devil as well!
"I would sound only one note of caution: Cristiano may need just a couple more years before we can consistently say that he is right up there at George's level.
"And I think the key to that will be his performances in Europe.
"Cristiano is the best player in the Barclays Premier League by a mile and his performance as captain against Bolton was outstanding. If I close my eyes and think back to him running past Ricardo Gardner in the second half and almost getting his hat-trick, it could have been George himself out there.
"However, I think Cristiano just needs to up his levels in the Champions League. When he does, he will be sitting there right next to Bestie in the list of greats.
"I am sure it will happen and he has the time, of course. George was finished at United aged only 27. Incredible, isn't it? And Ronaldo is still only 23.
"The way Cristiano looks after himself and the way modern footballers are taken care of these days, he will play for a lot longer than George and I hope he spends most of those glorious years at Manchester United.
"Sir Alex Ferguson loves him. I know that because he has told me himself. So does Sir Bobby Charlton. They think the world of him and we are blessed at United to have him."