International Friendly: Netherlands v Ecuador
Van Gaal named his 30-man preliminary squad for the finals on Tuesday and half of those players will have the chance to shine in their attempts to make the final cut.
Five more individuals - Ajax goalkeeper Kenneth Vermeer, his club-mate Davy Klaassen, PSV winger Luciano Narsingh, Chelsea midfielder Marco van Ginkel and Twente striker Luc Castaignos - make up the rest of the 20-man party for Saturday's game at the Amsterdam Arena, though their hopes of making Brazil are already over.
Each of the players still in with a shout count their caps in single figures, ensuring the competition for places will be stiff.
Feyenoord duo Terence Kongolo and Tonny Vilhena will hope to make the senior bows at international level, as will three of the players in Ecuador's ranks.
Reinaldo Rueda's squad travelling to Netherlands is the same as his 24-man provisional World Cup selection - midfielders Carlos Gruezo and Jose Francisco Cevallos Jr will hope for a debut, as will experienced striker Armando Wila.
Twente attacker Quincy Promes was a surprise entrant in Van Gaal's World Cup squad, having only made his international debut against France in March.
The 22-year-old has enjoyed a strong breakthrough campaign at De Grolsch Veste, scoring 11 goals in 31 appearances and laying on eight assists and is determined to impress his national coach and book a spot on the plane to South America.
He told his club's official website: "I'm back step closer to my goal - going to the World Cup.
"Right now I'm at the final 30 and I think that is an achievement in itself.
"If you see where I come from, this time last year I played in the Jupiler League (on loan at Go Ahead Eagles)."
"I have had a good week and very beautiful experience. I look forward to the next week with new experiences."
The nations have met just once previously, in a 2006 friendly that ended in a 1-0 win for the Dutch courtesy of Dirk Kuyt's goal.
Netherlands will play pre-World Cup friendlies against Ghana and Wales before the tournament begins, while Ecuador finish their preparations against Mexico and England.
Van Gaal's side begin the tournament with a repeat of 2010's final against Spain before facing Australia and Chile in a daunting Group B.
Ecuador will meet Switzerland, Honduras and France in Group E.