Greenwood started Tuesday in United’s 3-0 victory over Brighton and opened the scoring for the Red Devils in the 16th minute only.
He later became a supplier when he scored Bruno Fernandes, after playing a perfect inch chipped pass to his teammate.
Berbatov told Mirror Football: “Greenwood, against Brighton, was like Ronaldo.
“His left foot is amazing with his vision, I don’t think a lot of signatures are needed to take United to the next level.
“They must be really classy players to make a difference, someone who is going to be better than the current team of players. ”
United boss Ole Gunnar Solskjaer also praised Greenwood after his performance against the Seagulls.
“He’s better,” he said. “You can clearly see that he is maturing and improving, he is only 18, so we will see more of him.
“I said it all year long, as long as we can put it in the surface and around the surface, it will create chances for us, but in this game, its hold-up game, its linking game and its general movement were fantastic too.
“It’s great when he can go inside and outside, left and right.
“He is a special talent, a special child that we will take care of, trying to become a top player.
“He’s fine now, but he’s still young and has a lot to learn. He knows it, but we have a special talent that we must nurture. ”
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