Lionel Messi is the world's best player and his longevity is a marvel to former Argentina striker Hernan Crespo.
Crespo, who scored 35 goals in 64 international appearances, sees Messi as the stand-out claimant to the title of the greatest footballer on the planet, ahead of Real Madrid rival Cristiano Ronaldo.
Barcelona star Messi turns 30 this year and has enjoyed more than a decade at the top of his game.
"Messi is simply Messi, it is needless to add adjectives" Crespo told Gazzetta dello Sport. "[He is] the best in the world.
"To play at least 10 years at the highest level - impressive."
Messi moved on to 41 club goals for the season with a double against Valencia on Sunday, but another of Crespo's compatriots is not enjoying such a fine run of form.
Gonzalo Higuain has scored just once in his last seven outings for Juventus, but Crespo backed him to come good.
"Higuain is going through a bit of a bad spell, he has not scored in a few games, but nobody can doubt a striker like him," added the 41-year-old.
"He has everything: a good head, right and left foot, he is clever and adept at leading, gritty to perfection."
The two will meet in the Champions League quarter-finals next month and Crespo sees Barca as clear favourites.
"I see it like this: if Barca and Juve are both 100 per cent, the Blaugrana pass, they are stronger," he said. "But even with Messi they did flop in the first leg against PSG.
"One thing is for sure, [Massimiliano] Allegri's side cannot make any mistakes, they must be in top physical and psychological condition."