Chelsea looks weaker now. You see Fiorentina and Real Betis they should not be underestimated against Chelsea. However, it is more clearer that Chelsea will win against any of the mentioned team because this is the only competition they are playing in, and the only trophy they might be able to get their hands on this season. Apart from fighting for a place in the UCL next season they need one trophy just like every other big team across other competition.
In fact, Chelsea this season has developed quite well compared to the previous season. It's just that their consistency is not that good, even lately in the last 5 matches, their performance has decreased quite drastically. Yes, out of 5 matches, they have experienced 3 defeats, and that really makes their position drop.
Fortunately, their competitors, Manchester City and Newcastle also experienced some very bad matches, so Chelsea can temporarily survive in 4th place and enter the UCL qualification, it's just that, we don't know even it will survive in that rank or not, because for the next, Chelsea will face Tottenham whose performance is also not consistent enough this season.