Madrid, June 28 -- Spain sensation Lamine Yamal has been warned that, despite his meteoric rise at Barcelona, he still has plenty to prove on the international stage.

Argentina legend Mario Kempes has challenged the teenage winger to replicate his club performances at the FIFA World Cup if he wants to establish himself as one of football's true superstars.

While the footballing world has been captivated by the emergence of the 18-year-old winger, Kempes has urged caution, insisting that success on the international stage is the ultimate measure of greatness.

The 1978 FIFA World Cup winner believes the scrutiny and pressure of the World Cup far exceed those of La Liga, arguing that true legendary status is earned only by players who can...