Greenwood has exploded onto the scene with United this season, scoring 16 goals this season.
He has made the right wing position his own since the Premier League restart.
"There are not many players his age of that level," Matic told Stats Perform News.
"He has this natural instinct for goals.
"There is a big difference from now to six months ago. He is young and he is changing, and his approach to training and to everything is different.
"He's a great person, great for the changing room.
"He is quiet, I have to say, but the boy is always very positive and we are happy to have him in the team."
The Serbian added: "I don't want to put too much pressure on the lad [to compare him to others], but if I had to say someone, it would be [Arjen] Robben.
"I think that when he has seen players who came through the academy, he has seen Marcus [Rashford] as a role model and he has tried to follow those steps, it was easier too for him to see that someone can achieve big things coming from the academy, so I am happy for him," he added.
"It is important to have players from the academy. They are making big players, good people, it's important they are good people for the changing room.
"The expectation from our fans is high and they have to be ready to play at the highest level."