“For me, he has been in the under-21s with England, he’s tasting it more and more. And his appetite for football must be growing.
“I just don’t want to put too much pressure on him, apart from, ‘go out there and enjoy yourself’.
“Work hard, close down, because when the ball lands in your feet I know you’re going to score anyway. I know you’ll make the right finish. Keeper might make a fantastic save but he’s one of the best finishers I’ve seen.
“It’s just that enjoyment, express yourself, go out at Old Trafford because there’ll be 11 Astana players living the dream tomorrow.
“It must be one of the biggest games of their careers for some of these players, but I want it to be a memorable one for our players as well and Mason is one of them.”
Solskjaer has confirmed fellow academy graduate Axel Tuanzebe, 21, will be in the line-up against Astana, 28 months since last starting a match for United at Old Trafford.
A knock sees Daniel James join Paul Pogba, Anthony Martial and Luke Shaw on the sidelines, while Fred comes into midfield and back-up goalkeeper Sergio Romero gets the nod ahead of David De Gea.