The Portuguese secured his first victory in pre-season with a 2-0 win over Wigan Athletic at the DW Stadium on Saturday.
Will Keane and Andreas Pereira scored the goals, while Mourinho’s summer signings to date, Henrikh Mkhitaryan and Eric Bailly, impressed against the Championship club.
Tuanzebe was brought on for Bailly after the 80th minute but Mourinho is adamant that the 18-year-old centre-back impressed during that short cameo.
“You can play 90 minutes or one minute, sometimes one minute is enough,” the United boss told MUTV.
“With Axel, 10 minutes is enough.
“I only needed 10 minutes to know his potential, you can see it immediately.”