It won't be too difficult for Arsenal to secure a victory against Sevilla, even though they're playing away from home. Arsenal's fate is still in their own hands.
Well Arsenal are in a better condition to win the game based on their performances in the this season however they lost their last UCL game against Lens therefore I don't think they'll be ready to concede another defeat against Sevilla, judging from both teams performance currently it's very obvious that Sevilla are the weaker side even though they'll be playing with a home advantage, they're currently 14th in the Laliga standings why Arsenal are 2nd place in the EPL and recently won the champions league holders Manchester City.
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.