This is just a pre season friendly match. We have seen Manchester United performed very good in pre season matches in the past and crumbled during the season. It's good that they have won two premier league teams in their pre season matches, but hope they can win them where it matters. I would prefer them losing in the friendly matches and win in the league matches against these two teams they have played so far.
I agree with you. Infact to further support your claim, Man UTD in the last three years preseason games have been exceptional, but suffer in the league so it will not be okay to start praising them yet till they can be able to repeat this performance when the season starts.
The format in which they are playing this is like a series that at the end would result in an award of sorts so that's the thing with Man UTD, when they know that what they are playing for, a prize is attached, you'd see them coming all out and giving their best. I just hope that they can put this same mindset into their gameplay once season starts cause it doesn't sit well that a big team like them are struggling in the lower part of the table.