Juventus goalkeeper and captain Gianluigi Buffon feels like Ronaldo was "created in a lab" as he lauded the Brazilian icon.
Ronaldo dominated during his illustrious career, winning titles with PSV, Barcelona, Inter and Real Madrid, while he helped Brazil to World Cup trophies in 1994 and 2002 as he won three FIFA World Player of the Year awards and two Ballons d'Or.
Asked which strikers caused him the most problems, veteran Italy international Buffon heaped praise on the 40-year-old.
"The striker who caused me all kinds [of trouble] was Ronaldo, the Brazilian one," Buffon, 39, told Marca.
"He was the perfect player, as he had power, speed, intuition technical skills and quickness. He was a jaw-dropping player.
"It seemed like he was created in a lab."
Ronaldo earned 98 caps for Brazil following his debut in 1994, scoring 62 goals — only second to all-time leader Pele.