Well Sevilla is not a team to be underestimated cause they're not very good at attacking but they've can be very good defensively on a good dsy and their defense can cause alot of problems for Arsenal's front 3, Arteta should just hope another player from their front 3 doesn't sustain an injury in that match.
I am quite sure that Arsenal will be able to beat Sevilla in the Champions League match, this season Arsenal is very good and managed to win the match against Manchester City who once won the Champions League, although Sevilla appears superior because they will play at home but Arsenal is a tough club when facing away and home matches .
Sevilla is not in a condition after changing coaches. I don't think Sevilla has been able to fully adapt to its new coach so that this match is enough to enable Arsenal to win and be able to take home points from Sevilla so they can continue to the next round.
Looking at their last match Arsenal against Sevilla in the Emirates Cup, Arsenal was able to score a fantastic goal against Sevilla namely 6:0 so I am quite confident that Arsenal will be able to qualify for the next round to face UCL this seasons.