Robert Pires says not even his former France team-mates Zinedine Zidane and Thierry Henry played at the same level to Lionel Messi, who "has something no one else has".
Pires enjoyed a distinguished career and won many major titles playing for France, Arsenal and Marseille, playing alongside some of the world's biggest stars.
Arguably chief among them were the likes of Zidane and Henry, with whom he won the 1998 World Cup under Aime Jacquet.
Pires joined Villarreal in 2006 and his four-year stay saw him feature against a number of other modern greats, including Ronaldinho and Cristiano Ronaldo.
But, for Pires, none of them – not even Zidane and Henry – hold a candle to Messi.
"If he plays like he did against Espanyol, it is impossible to stop him," Pires told Mundo Deportivo. "It was incredible.
"I have played with Zidane, Henry and [Juan Roman] Riquelme, and against Ronaldinho and Cristiano, but Messi has something that nobody else has.
"I don't know if he is the best in history, but there are few where he is."
Messi could have been playing in a front three with Antoine Griezmann, a compatriot of Pires', had things turned out differently before the World Cup.
Griezmann was strongly linked with a move to Barca, but in the end he opted to remain with Atletico, a decision Pires thinks was probably wise.
"It was his decision and you have to respect it," Pires said. "He thought that it was the best place for him to play, because my question is: where would he have played if he had gone to Barca?
"You do not take away Messi from [Luis] Suarez, or vice versa. They are superior to Griezmann, who could play some matches, but not all of them, as is the case at Atletico. That is the difference."