The kid is good but let's not get ahead of ourselves.
Admonition well taken, but a stronger adjective than just "good" to described Mason Greenwood is fully warranted.
We forum posters can easily carried away, so let's take a look at what someone who knows a thing or two about United attacking players, Dwight Yorke, has to say about Mason Greenwood:
"He is better than Rashford, looking at his record now. You got to understand though he is still 18, at a development stage. Having Ole there, he would guide him along the way."
What is impossible to deny is that since the restart Greenwood has been substantially better than Rashford. But we could attribute that to Rashford not being fully fit and Greenwood simply being on a hot streak while catching opponents unaware of how good he really is. Those are not strawman arguments but very real possibilities. Yet when we watch Greenwood perform we see a genuinely two-footed player, which can't be said of Rashford, and we see a forward who's a much cleaner striker of the ball than Rashford, at least inside the box.
As for Anthony Martial, his performances have improved substantially in the second of this season, it wasn't that long ago that most of the Caf (myself included) were drooling at the prospect of upgrading the 9 position with Haaland, as Martial had stagnated for a long time both under Mourinho and Ole. But he's in fantastic form now, and although most of us would rather have Haaland than Martial, it's pretty safe to say Martial wears the 9 quite well.
Some stats and then I'll wrap this up:
According to WhoScored, which I think is accepted as a reliable database, these are the minutes played this season and goals scored (and assists):
Greenwood
Total Minutes: 1773
Goals 18
Assists 2
98 minutes played per goal scored
Rashford
Total Minutes: 2170
Goals: 21
Assists: 7
136 minutes played per goal scored
Martial
Total Minutes: 2916
Goals: 22
Minutes: 6
132 minutes played per goal scored
Yes, let us refrain from getting ahead ourselves. But let's also acknowledge that we've seen with our own eyes a young footballer perform at an extraordinary level this season, score crucial goals for us during the restart, as did Martial no question, and turn in mature performances and not just moments of flash that led to a few surprise goals against unsuspecting defenders.
Gary Neville is quoted as having said yesterday
"I think he’s intelligent on the pitch, can do things the other two can’t do, he’s a better finisher and I think he’ll end up taking that no. 9 spot in the next 12-18 months."
The last bit remains to be seen, but doubts Greenwood's ability are nonexistent and it seems highly unlikely that if we do bring in Sancho that Greenwood will be a super sub for United for years to come while he watches Rashford, Martial and Sancho steal the spotlight. If we do bring in Sancho, it's very easy to see Greenwood taking that no. 9 spot from Martial in the next 12-18 months. We shall see.
Neville completed his thoughts when he said
"I think he [Greenwood]’s the best striker that Man Utd have and will score as many goals as he wants to. "He just has to keep fit and keep himself grounded and remember what he said, that football comes first." We shall see whether Greenwood keeps himself grounded and that football comes first, but he cuts the jib of mature footballer already will keep himself grounded and continue his progression.