The 20-year-old was included in the last five match-day squads of last season as Mourinho rested key players for the Europa League final and made appearances against Arsenal and Crystal Palace.
He enjoyed a promising pre-season and has continued to train with the Man United first team, making his first appearance of the campaign against Burton Albion in the League Cup.
And McTominay, speaking to MUTV, was quick to note that he was learning every day under the 54-year-old’s tutelage.
“You have to think quicker, you have to be quicker on the ball, and you have to move your feet quicker,” he said.
“You just have to be switched on so much more than the Under-23s games. Eventually, you will just end up adapting to the scenarios within the game, moving your feet quicker, checking your shoulder and everything, he added. So it’s been great for me to be training in this kind of environment and I can only get better.
“The 6ft 4in midfielder also admitted now he has had a taste of first-team action, he is eager for more, and that he is constantly trying to make an impression on Jose Mourinho when given the opportunity.You always want minutes and that’s what you work for every day in training.
“Training with the first-team group is a massive step up in standard and it’s brilliant for me to be training in this environment because you’re only going to get better with these guys coaching and playing with you every day.
“You just adapt to their standard and want to improve yourself as much as you can and be ready to play in games like this in the future.”
Mourinho evidently sees something in McTominay. He is by no means a breathtaking talent, but rather an honest worker – somebody who can align with the physical and tactical demands imposed by Mourinho with little trouble or fuss.
But being a studious worker isn’t enough, of course, to breach the first team. There is a subtle air of natural talent to the midfielder’s game: his touch, weight of pass and positional sense comes easily – both fluid and progressive.
Supporters will hope to see the youngster continue to make an impact as the campaign goes on.