I doubt that Arsenal will be playing in Europe next season.
A defeat against Manchester City was bad enough but we had a game in hand before then. We needed to win all our remaining league games to have any chance to qualify for European football by finishing high enough in the table.
So the defeat to Brighton was a bad one. A misfire by the Gunners. Which means our only hope of qualifying to play in Europe is the FA cup. We are up against Sheffield United in that and even if we get past them, with teams like ManUre, Chelski and the Team That Rhymes With City in it, we are unlikely to win it.