Manchester United were a bit lucky, the whole game was possessed by Arsenal, if Arsenal attack was as strong as Liverpool then the number of goals in that match would be more numbered than yesterday score line. Arsenal had no progressive attack, they focused on one part of the field which United was aware and capable of defending themselves, a more better performance from Arsenal would have given them the winner but they were unlucky to share points when they needed it the most.
I think this match was a bit really about luck with the way I watched the match. Manchester United also did well in their performance; they did not perform poorly as we were thinking before the start of the match, although I know they were ready because they know how strong Arsenal is, and that is why they came ready to play the match.
However, this is the time Arsenal needs this win the most, and they failed to win this match, which is very bad for them. They should be the ones to at least record this 1 goal; it would have been better for them, but Arsenal failed to win the match. Although, as you said, the possession of the match was with Arsenal, but not luck to win.