Newcastle United is a strong opposition but Arsenal should hope for a draw of they can't win but against Southampton that held Manchester City to a goal less draw Arsenal needs to take 3 points from them.
We have not seen Arsenal play well in the last three matches. They have failed to win against Liverpool, Bournemouth and Crystal Palace. They have also played badly against PSG in the Champions League. Their opponent Newcastle are in good form. Now the team is trying to grab the second place in the table.
An interesting thing is that Arsenal have lost their last three matches against Newcastle. Newcastle have been very strong in the last few seasons. Arsenal have also lost 2-0 in the away match this season. It is not possible to say for sure whether Arsenal will win the home match. I would agree with you that since Arsenal are not in good form, they should try to share the points in this match.