Mejbri is on-loan at Brum this season.
Speaking to Birmingham Live ahead of his trip to Middlesbrough, he said: "I need to play some games, that's why I came on loan, get some experience, it's always good to be part of a team that is playing in the Championship.
"It is very different to Manchester United, we play different football but it's good, I am here to learn, it's more defensive, more box to box, so I have to use it to get ready for United. I just want to play games because that's how we learn, that's how we improve, when we play games, when we are around the team and come on, 30 or 20 minutes, that's how we learn to manage the game, we win some experience.
"I am very patient; I wait for my time and hopefully I will be ready when I get my chance."