For me I think Newcastle are playing with the happiness of winning a trophy this season, ever since they won that trophy their performance has been wonderful and they are just flexible, their runs and marking has been great but I feel it will expire soon because we all know Newcastle how they are not as serious as they can be, playing a draw losing games they are suppose to win and now they display something different and I'm still not trusting this new style of winning and performing well every week.
Newcastle Uniter has already achieved something this season, they are better than many big teams in the EPL right now because they have something to take home already; the only thing they need to do before the end of this season is to secure the Champions League spot which I think will be the main reason why they will never wanted to lose any maych because they know how well competitive it will be since Manchester City, Chelsea, and Nottingham Forest are also in the race, so they need to be very serious by winning all their matches to make it to the top four.
For Arsenal I don't think they'll be dropping any game because of Champions League, every game for them is important but the problem is how serious are they going to take each game both the EPL game and the CL game? Is just a mattee of time to see how good they can manage the remaining games.
Every match is important for Arsenal, they can’t afford to lose any Premier League match because their position is not stable, the teams behind them are serious, they are trying to overtake them and because of the force they are using, they can both keep winning their respective matches which will result to Arsenal’s position to be at risk because the once Arsenal lose one match, they will get closer to them and they might lose their position; therefore, I believe that Arteta will rest some players, but they will never lose anyhow.
You're right, Newcastle are better than some of the bigger clubs that we expected would show more action this season, they deserve that win and they can never forget. I know why I'm saying this, although they might have a way to the top but their game at hand is what is giving them hope if taking that 4th position from either Chelsea or Man City or whoever is sitting at that position. If Newcastle can keep this nice form I don't have a problem but like I said, I can't trust them just like I don't trust Arsenal till the job is done.
Between the EPL and the CL I can't say which one is easy for the Gunners to get as it stands now, they are not as close as they can be in the EPL table and the champions league is still tight like no one knows who'll win it because more drama and surprises can happen so Arsenal can't be seen as a possible candidate to win it until it is done which we know is very hard for them.