Roberto Carlos says that there will never be another Ronaldo, arguing that not even Lionel Messi, Cristiano Ronaldo or Neymar compare to his former Brazil team-mate.
After announcing himself to the football world with a sensational 1996-97 campaign at Barcelona, Ronaldo was subsequently hindered by knee problems over the next five years.
He returned to full fitness, however, in time to fire Brazil to victory at the 2002 World Cup, with his heroics in Japan and South Korea earning him a move to Real Madrid.
Ronaldo went on to spend five years at Santiago Bernabeu playing alongside Carlos, who says that his compatriot was the outstanding talent in a group of superstars that came to be known as 'The Galacticos'.
"Ronaldo stood out in training. He was the best. There will never be another Ronaldo 'Fenomeno'," Carlos told Goal after the Challenge Heineken Legends. "Not Neymar, Cristiano or Messi – Ronaldo is unique.
"I think in our generation it was harder to score goals. It was more physical back then and attackers were less protected. But Ronaldo could do everything."
Even after his World Cup heroics, the injury-prone Ronaldo was greeted with some scepticism when he joined the likes of Luis Figo and Zinedine Zidane at Madrid in 2002.
However, as Carlos fondly recalls, his compatriot dispelled all doubts over his fitness with a brace on his debut against Alaves.
"I knew how unbelievable he was when he arrived but a lot of people at Madrid didn't," the legendary left-back added. "He surprised a lot of people. I remember 80,000 people were very happy and pleasantly surprised by him."
Carlos has nothing but fond memories of his 11-year stint in the Spanish capital, revealing that even though the dressing room was packed with some of the biggest names in football, they all put their egos to one side for the sake of the team.
"We had an amazing atmosphere inside the club," the 47-year-old enthused. "Even though there were huge players, it was just a group of great people working in the same environment. We were all great friends and still are.
"It was spectacular. Real Madrid is bigger than egos. The club is huge and the culture of the club was so big that we were able to sign huge players. It was then up to the players to adapt to the culture and not the other way around.
"Everyone had to speak Spanish in the dressing room. The only one who decided to speak more Portuguese than Spanish was [David] Beckham because he wouldn't leave my house! He was close to Ronaldo and me, so his Portuguese got better than his Spanish."
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Of course, Carlos' former team-mate Zidane has gone on to enjoy great success as Madrid's coach. Indeed, the Frenchman is presently in his second spell as boss, having led the club to three consecutive Champions League titles before stepping down in 2018.
Carlos, who still works with Madrid as a football ambassador, is not in the least bit surprised that Zidane is proving just as big a hit at the Bernabeu as a coach as he was as a player.
"Zizou arrived as the number one in the world," he said of the former attacking midfielder, who joined from Juventus in 2001. "He is not one to speak a lot, so he let his football do the talking on the pitch.
"He was like an artist or ballet dancer. He is one of the best of all time without a doubt. And also one of the best coaches in the world right now.
"He is great on the human side. He creates a good relationship with his players and he knows the mentality of Real Madrid. He made it simpler for players to work and he knows how they think.
"They are so happy with Zidane that they won three Champions League trophies in a row; that says a lot about him!"
Zidane's big-money signing last summer was Eden Hazard, who has endured a difficult, injury-hit first season in Spain.
However, Carlos is confident that the Belgium international will end up filling the void left by Cristiano Ronaldo and Messi when the pair eventually retire.
"I still think they have another three years at the very top but Neymar, [Kylian] Mbappe and Hazard will take over after Ronaldo and Messi," he stated.
"Indeed, Hazard, in a short time, will prove he is number one in the world."
As a player, Carlos looked beyond football to Formula One for inspiration and often went to watch races whenever he had a Sunday off.
It's hardly surprising, then, that he is now relishing the opportunity to compete with Nico Rosberg and David Coulthard in the Heineken Legends Challenge esports events.
"It is really exciting to go against some of the biggest racers in the world," he enthused. "I used to go a lot to F1 when Real Madrid didn't play at the weekends. It was a lot of fun and I always wanted Real Madrid to play on a Saturday so I could watch F1 on Sunday!
"I spent a lot of time with Michael Schumacher. I have a lot of friends in the game like Felipe Massa, Giancarlo Fisichella and Rubens Barrichello.
"Ayrton Senna is the Pele of F1 for me. He is the number one for us Brazilians so he left a huge impact on me."
Roberto Carlos took part in the F1 Esports #ChallengeHeinekenLegends, on Sunday, May 17. Search #ChallengeHeinekenLegends or visit https://www.heineken.com for more info.