Matic signed a new deal to 2023 yesterday and was asked about Greenwood's two-goal performance against Bournemouth on Saturday.
The Serb told manutd.com: "Yeah, it's great. We're scoring goals, of course, and that's nice, but it's always important to keep the ball up front. It's easier for us then at the back to defend and control the game when we lose the ball.
"I'm happy that they're playing with more confidence, most of the time we have the ball so I'm happy for our strikers that they're keeping the ball, controlling the game and scoring goals. You mentioned Mason, I'm very happy for him. He's a very young player, but he scores a lot of amazing goals – especially the second one, with his right foot. I'm happy for him, for sure he will be a very important player."