Yamal blew a fuse at Flick at the end of last weekend's LaLiga win at Atletico Madrid, with the blow-up being played out in front of watching cameras.
But Flick insists there is no issue with the teen and ahead of tonight's Champions League quarterfinal first-leg clash with Atletico Madrid said: "I already said on Saturday after the game that he tried everything.
"He had the ball, we switched wings... Lamine is 18 years old, and for me, he's an incredible player. Sometimes, in the replay, you see that what he does is amazing, but he's only 18, and sometimes he gets angry if I substitute him or if he's been in a situation where he's had four or five players on him, shot, and missed.
"It can be frustrating if he doesn't score, but he's a passionate player, and I support him. He's on the right track, and we're helping him develop in the right environment. Not everything he does has to generate a lot of buzz. I know everyone has their eyes on him because he's a fantastic player, but he's only 18.
"I've told him that he can make mistakes, and that I'll protect him. He'll be one of the best, or the best, players in the future."