Arsenal team should have given PSV more goals, but they failed to win by 1 goal. But Arsenal's next game is against Southampton, I expect Arsenal to win that match too. However, it is his personal matter who the Arsenal coach will give a chance to the team in that game. Because remember Arsenal don't want to lose.
One goal is more than enough, as long as you beat the other team and you have a chance to continue to next stage, that's enough. Next opponents will not be so easy, Barcelona, Ajax, and many other great clubs from UCL is coming to Europa next up, and that's going to be very tough, they shouldn't tire themselves out on Europa, they will be very tired when the time comes plus Premier league is still going on and they are winning there, so it will be very important to keep both sides going, and I think FA cup will be very tough too.
When a team is playing in 3 different competitions, you can't expect them to have games of 5-0 or whatever that commonly, they will relax and actively rest during the games if they are winning.
Yes I agree with you. For Arsenal, victory is certainly very important for them to get, even if only by a narrow score of 1-0. This victory makes Arsenal have locked a ticket to the next round in the Europa League. Arteta certainly doesn't want to focus on just one competency, so with this win one job is done (in the group stage) and Arteta will instruct his squad to focus on domestic competitions. The Gunners must really take advantage of all the matches at this time before entering a busy period in December which will certainly be very energy-consuming.