Mason Greenwood: Man Utd boss Ole Gunnar Solskjaer says he 'cannot leave out' teenager
The English forward, 18, took his tally to 16 for the campaign by netting in United's 3-0 victory at Aston Villa.
Only George Best, Brian Kidd and Wayne Rooney - all with 17 - scored more as teenagers in one season for United.
Solskjaer said "it's up to him [Greenwood] how far he wants to go".
Greenwood ‘outstanding’ in the first-half - Solskjaer praises youngster
Academy product Greenwood has shown during his breakthrough season why he is rated so highly at the club, showcasing pace, skill and the ability to finish with either foot.
His goal against Villa was smashed in from 20 yards out with his right foot, as he became the fourth player aged 18 or under to score in three consecutive Premier League games, after Danny Cadamarteri, Michael Owen and Francis Jeffers.
Solskjaer said: "I am doing my bit to help him but he has to do it - turn in performances in training, in games, live his life properly. It's up to him how far he wants to go.
"He's 18 and of course he will get better. He is a natural footballer and has been in the academy since he was a little boy. His dad showed me a picture of us together when he was seven. He knows we believe in him. You cannot leave players out when they score goals."
United goalkeeper David de Gea told BBC Radio 5 Live that Greenwood has "everything in his hands", adding: "He is a great player, a top finisher. You don't know if he is left or right-footed and it is great to see the kid scoring goals like today. We have to have some patience with him because he is young."
Former United and Villa striker Dion Dublin said on Match of the Day: "Mason Greenwood is getting better, quicker.
"When you've got three or four rockets running away from you, [Villa defender] Tyrone Mings goes too deep. The strike… I thought he was left-footed - what a future he has got."
We are producing performances worthy of Man Utd - Pogba
Paul Pogba celebrates
Pogba scored his first goal of the season
Another United player who has impressed since the season restarted is midfielder Paul Pogba, who looks to be getting back to his best after an injury-hit campaign.
The future of the France World Cup winner - who has a year to run on his contract - has been the subject of constant speculation, as he has been linked with moves to Real Madrid and Juventus.
But there may be signs he is willing to stay at Old Trafford after he said that "Manchester United is a big club".
Pogba stroked in his first goal of the season - and the 3-0 win meant United became the first side in Premier League history to win four consecutive games by a margin of three or more goals.
The last team to achieve the feat in the English top flight were Liverpool in October 1987.
Pogba said: "We are really pleased with ourselves because we know we have to carry on. We talk before the game, in training, Manchester is a big club and we want to keep the level up always.
"The performances of the past few weeks are Manchester United. We have to keep working, there is a lot to do."
Solskjaer added: "We still have a contract with Paul. He is a fantastic person, fantastic player - one of the best midfielders in the world.
"It's a different team to the one he left when he was injured. Everything is miles better in that dressing room."
De Gea added: "We are in a very good way. Now I feel we are a team. Everyone is on the same way, everyone wants to win, to help and I am really happy.
"It is great to see my team-mates play like today."