Ronaldo, however, then sat out the start of United's Champions League match against Aalborg at Old Trafford. The Red Devils have already secured a spot in the knockout phase of the competition, and Ronaldo was rested ahead of the team's Premier League match at Tottenham on Saturday.
Law was the first United player to win the Golden Ball award in 1964, with Charlton capturing the trophy two years later. The late George Best won the award in the wake of the team's 1968 European Cup triumph.
The 23-year-old Ronaldo scored 42 goals and helped United win the Premier League and Champions League titles last season, his fifth with the team.
"He took my breath away then, but he was over the top," said Charlton, who scored 198 goals for the Red Devils from 1954-73.
"Some of the things he did were just too much and wasn't really effective. He has learned when to do these things at the right time, and without doubt he is still getting better.
"I get excited by watching him. If you are struggling a little bit he is a player who can turn a game with one bit of skill." Even Charlton's grandson is impressed, often emulating the Portugal winger instead of England's leading goal scorer.
"When we go out in the back garden all my grandson wants to be is Ronaldo, with all the stepovers and tricks," Charlton said.
"All kids do it because people love players who do something special. "That is why Ronaldo gets compared to George Best so often. It is not bad for the game that kids are emulating skill like that."
