The retired Frenchman was fortunate enough to play with both of the incredible Ronaldos during his 17-year professional football career.
He played with the Brazil legend in the 1998/99 season when they both plying their trade in the Seria A for Inter Milan, and C. Ronaldo at United between 1999-2008.
Whilst Silvestre admits they both were/are incredible players the Brazilian Ronaldo for him was a better footballer.
He told Goal.com: "Both of them were great. Both of them very good team-mates and more importantly great human beings, but the Brazilian Ronaldo was out of this world. He was phenomenal.
"You can't really compare them as one was more a No.9 and the other was a winger. They play in different styles and positions.
"But Ronaldo was [the best I ever played with] because he was a natural talent. Even when he was injured and overweight, he was still very good."
It's a very bold claim from the former United and Arsenal defender. Ronaldo was an international hero for Brazil scoring 62 in 98 appearances for his country.
He trumps C. Ronaldo in that department, but at club level is where the Portuguese man really excels. Currently 29, C. Ronaldo has scored an unbelievable 375 in 569 games in all competitions for Sporting, United and Real Madrid.
The 2002 World Cup hero has a better goals to game ratio than his counterpart with 352 goals in 518 games; a ratio of 0.68, whereas C. Ronaldo's goals per game ratio is 0.66.
However Ronaldo retired at 34-years-old, and in the next five years Cristiano is almost guaranteed to surpass his ratio. Although admittedly the Brazil man would have scored many more goals had his career not been blighted by long-term injuries and fitness problems.