Newcastle have strengthened very good this season and this has had a positive impact on their results. What can be expected in this match it is hard to say, because there are many components here
All started in the past season when they had a new owner and bought some good players but back in the last season, they don't have enough time to use new players well.
One summer and pre-season training are enough for them to be strengthened like now. I believe Newcastle will become stronger in next season if they can complete this season at high rank enough to join either Europa League or Champions League in next season. It will make them more attractive for star players and they will have better ability to convince star players to join their clubs.
With star players, some of them care more about their career, chance to win titles rather than only about salary.
on the one hand Manchester United are playing at home, on the other hand they concede more than they score, and against a team like Newcastle, who have everything in order with attack, the game can be difficult. I think Manchester United have a chance to win, but the match will not be easy for them, and I think that both teams will score in this match.
Only in theory, having a home stadium and home fans are great support but Newcastle can pass through it and leave with three points. They have ability and enough resources to achieve 3 points. Manchester United shows improvements but they are still in between good and bad. We can not say their next match should be a good one if they just had a good one previously.