The Red Devils and Barcelona are set to do battle in a pre-season clash in America soon, which will pit the Dutchman against his former club, where he coached on two separate occasions.
Messi has been a fulcrum of the Camp Nou side for some time, with his sparkling form this year firing the Blaugrana to a momentous treble in Luis Enrique’s first season in charge of the Catalan club.
Van Gaal, who is frequently outspoken and critical, has admitted that he has respect for Messi for both his ability and his attitude.
"Messi proves himself nearly every game,” Van Gaal stated to the United official website.
“Despite his immense talent, he remains very modest. I like that in him and I respect Messi a lot.”
Messi continues to break individual records on a frequent basis, with his goalscoring exploits and skill on the ball seeing him in line to potentially win a unprecedented fifth Ballon d’Or award.
The Argentina international’s season came to a disappointing end however, with defeat on penalties in the Copa America final against Chile.
Messi will be one of the major draw cards when the teams meet in America, with the 28-year-old widely regarded as the best player on the planet.