Messi gave me sleepless nights — Real Madrid legend Casillas admits

The iconic goalkeeper, who enjoyed a glittering 16-year senior career at the Bernabeu and captained Spain to World Cup and European Championship glory, faced some of football's greatest attackers during his prime.

Yet none troubled him quite like the Argentine superstar. Casillas came up against Messi on 26 occasions and conceded 17 goals to him, the most by any player in his career.

Messi even scored both of the only two hat-tricks Casillas ever shipped in more than 1,000 senior appearances.

While Casillas was a teammate of Cristiano Ronaldo for several seasons at Real Madrid and only faced him a handful of times at international level when Ronaldo represented Portugal, it was Messi who consistently caused him the most problems.

"The striker that gave me sleepless nights? Messi," Casillas said.

When asked who was tougher between Messi and Cristiano, he added, "I never had to face Cristiano at club level, though I did play against him with Portugal, but I think Messi was harder."

Casillas is far from alone in his assessment. His words have been echoed by countless current and former players over the years, as Messi has tormented some of the greatest goalkeepers the game has ever seen, from Gianluigi Buffon and Petr Cech to Alisson Becker and beyond.

Now 38, Messi will be playing in what is widely expected to be his final World Cup this summer, as Argentina look to defend their title and become back-to-back world champions for the first time since Brazil achieved the feat in 1958 and 1962.