However, they will face tough opponents in December, including Brighton, West Ham, Liverpool, and Aston Villa. I find it hard to think that Arsenal will be able to defeat the four clubs given that they still have one Champions league game left to play. They can win like two out their next four premier league matches.
I don't think their match against PSV will really change anything on the Champions League table. If PSV wins, they will remain in second place with 11 points, and Arsenal will remain at the top of the standings with 12 points. This month Arsenal will face teams from the top 10 of the Premier League standings. This means Arsenal will focus more on tough matches in the Premier League in December. It is likely that they will try to rotate players against PSV, perhaps by playing some reserve players and young players because whatever the result will not change anything in the standings.
The game is irrelevant in the Champions League for Arsenal. They can now give some talents a try to show their quality in the Champions League, which I think would be the right course of action here when a team has players that haven't yet made the experience on the biggest stages.
Arsenal can fully concentrate on the Premier League games ahead of them and the Champions League game is the perfect possibility for them to give some players a rest as the big weeks around Christmas time, the boxing day, are also coming.