Ighalo has just extended his loan from Shanghai Shenhua to the end of the year.
Schmeichel told the Daily Express: “I think he's been one of the most positive surprises ever.
“First of all his personality around the club, he's been a revelation around the club. Everybody has tagged on and liked him straight away.
“When you have that kind of personality, it changes the whole team. Someone who brings a laugh into the dressing room, rather than coming in grumpy or not saying anything.
“It changes the dynamics. And what he's done on the pitch, that really has surprised me.
“I was kind of confused…because it was last day and it looked as if they were just needing and looking to bring someone in.
“But that's not the truth. And what he's done is just fantastic.
“And another thing as well, someone like him, all of his life the only thing he really wanted to achieve was to play for Manchester United.
“Now that has been cut short by circumstances that are out of everybody's control. And for what he's done, in the very few games he's ended up playing, it would have been heartbreaking if that was to stop.
“I think he might not be a starter but he might be somebody you can throw into the mix. You've seen him in the Europa League, like Ole himself, he can come on and change a game.
“Nobody, nobody, knows that better than the Manchester United manager. The value of having someone on the bench who can change a game, so I'm really happy about that."