The Dutch star, 22, has struggled to hit top form at Manchester United since making a summer move from PSV Eindhoven.
He’s been hammered by critics who claim he’s been too busy enjoying the party lifestyle.
Memphis disputes that while Van Gaal continues to back his fellow countryman.
He said: “I saw him in the first year that I was national coach.
“He came into the squad to substitute for a player from PSV Eindhoven and he only played ten minutes but I said to my colleague ‘he is a player, he can play’.