Sporting Lisbon youth coach Aurelio Pereira says that Cristiano Ronaldo was more of an "artist" as a youngster but has since developed tactically and physically into a goal scorer.
Aurelio has overseen the emergence of stars including Paolo Futre, Luis Figo, Simao Sabrosa, Ricardo Quaresma and Nani during his time at Sporting, as well as more recent players such as William Carvalho and Gelson Martins.
He was also there when Ronaldo arrived at Sporting as an 11-year-old back in 1997, and believes there was more "fantasy" about the way the Real Madrid forward played as a boy.
"As a boy, Cristiano was more of an artist than today," Aurelio, still Sporting's youth recruitment and youth development chief, told AS. "Today he is more an athlete, as he has changed, remodelling his body to meet the demands. He has moved from a fantasy footballer into another more physical type of player."
Aurelio said that when Ronaldo first arrived in Lisbon from Madeira club Nacional, the youngster covered the whole pitch in each game, but over time he has since "transformed himself" to focus on scoring goals.
"At the start, Cristiano was not a goal scorer, he was a box-to-box player," he said. "Aged 11, he used both left and right foot. He defended well, he occupied the whole pitch, he was fast and skillful, even good in the air. He was a complete player.
"[Over time] he has transformed himself with training and in the end became a goal scorer. He changed his own way of playing to become what was valued most."
Ronaldo -- who faces Sporting with Madrid in the Champions League on Tuesday -- always had a special talent but needed to work at it to get the most out of himself, said Aurelio, who compared the footballer to classical music genius Wolfgang Amadeus Mozart.
"They say that when Mozart was six years old he had already done 3,500 hours of practice on the piano," he said. "Cristiano is like that, a natural talent, but who has always worked on it. Having talent is not enough to be a genius, you must put in the work."
Portugal coach Fernando Santos also used classical examples when asked in an El Pais interview whether Ronaldo or Lionel Messi of Barcelona should win the 2016 Ballon d'Or.
"For me Cristiano is the best, although I have always been reticent to compare geniuses," Santos said. "Da Vinci, Rafael or Michelangelo, who is the best? It is about your taste. But if we speak about just this year, Cristiano is the best. He won the Champions League and the Euros. There is no doubt that this year Cristiano must win the Ballon d'Or."