After overcoming Real Sociedad in the round of 32, the Red Devils were drawn against the Serie A giants who got past Crvena Zvezda on the away goals rule.
The Red Devils will be reunited with Ibrahimovic and on-loan defender Diogo Dalot and the Norwegian believes they are coming up against a top side.
"We just continue our tradition of picking difficult teams," the manager told Sky Sports of the draw. "[It's] a tie that feels like a Champions League game as well, which is good.
"I think it's important for our team to always have that demand and not feel that it's a given. And of course this is not a gimme – Milan, they're on the up, they've done really well this season.
"They've got some former friends of ours. The history of the club is fantastic so we're looking forward to [facing] them."
When asked about Ibrahimovic, he added,"It's incredible what he's done.
"When we think back when he was here, when he had a career-threatening injury and the way he's come back, the way he's played, the way he's moved AC Milan towards the top of the league again.
"And of course Diogo is there. So we know that we're in for a good fight but before then we have a few other games that we have to look after."
