The match they will play tomorrow is critical because Chelsea is a team that is slowly starting to recover. Arsenal, which gained great morale by beating Manchester City, aims to keep its morale even higher by beating Chelsea. I think Arsenal can no longer be stopped by either Sevilla or Chelsea.
Arsenal not been stopped by Sevilla is very likely but my fear it that they are playing champions league which is very volatile and competitive unlike any other league, and this two teams are trying to make sure they secure a spot at the next stage of the league so it's very possible they will want to give Arsenal a tough one and even share points with the gunners except they perform better than Sevilla will.
Chelsea is giving a move that shows they are gradually improving as displayed in their last two matches were they got a win but then Arsenal has really proved themselves to be very formidable this season especially when they got a win over Manchester city it became obvious ho well they can perform, although it was a lucky win but then it has increased their morale and Chelsea would have to perform better than they have ever done this season in oder to get a good result from the match.