The teenager was introduced by Jose Mourinho in the 69th minute as a substitute for Timothy Fosu-Mensah but spent some minutes on the touchline awaiting a break in play to come on.
Tuanzebe says he could hear Ibrahimovic behind him giving him advice as he prepared to take the pitch for the first-team for the first time.
"I was on the touchline and I can hear Zlatan just saying 'keep it simple, keep it simple' so I followed his advice and I was just waiting for my moment and it finally came," he told MUTV.
"It was crazy, you know since I was a little boy I've been thinking of this and now it's come true. I'm over the moon, I'm still shaking now! You just can't really believe its happened but it's good for me and my family. I'm very proud.
"But now it's just getting back onto the training ground and going again. If I'm with the Under-23s, it's with the 23s, I stay humble and work hard to get another opportunity to play again."
United ran out comfortable 4-0 winners thanks to goals from Marouane Fellaini, Chris Smalling, Henrikh Mkhitaryan and Bastian Schweinsteiger.
Tuanzebe was not the only debutant for the Red Devils, as Mourinho also gave a first appearance to Joel Pereira who replaced Sergio Romero in goal for the final 10 minutes.