I can't say Man U played better than Newcastle, but I guess the home field factor played a major role... They were lucky in this match and to be honest their game was much better than the previous ones... Now Newcastle and Devils have the same number of points in the standings and there is a small chance to get into the Conference League if Chelsea lose to Bournemouth, which I doubt...
I was surprise Manchester United won the game last night against Newcastle United, there win against Newcastle United has given them a chance to qualify for the conference league if Chelsea losses to Bournemouth which I doubt just as you, but football can funny and unpredictable anything can happen Bournemouth can shock the world by winning Chelsea puting Manchester United in a better position to qualify for the conference league.
I know you were surprised by United's win over Newcastle; it was huge. Really big. They have a great chance of winning the Conference League. Its a long shot, though. Anything can happen in soccer, and Bournemouth beating Chelsea would be the shock of the century. Real shock. Bournemouth's had upsets before, so we'll see, but the season is ending and unusual things happen.
We shouldnt kid ourselves. Chelsea will not surrender against Bournemouth as they recover. United must concentrate on their game and win. No one else can aid them. They might finish well if they play like they did against Newcastle, with energy and determination. I sense some enthusiasm in these last games.