The position where Chelsea is currently is in the premier league stand, their is no guarantee thst Chelsea will surely secure the fourth position because their are teams under Chelsea that their points are even close to Chelsea, so any mistake from Chelsea these clubs can take over the fourth position. Chelsea has a lot of job to do to win every of their games till the end of the season.
From the way things are going, I don’t even think Chelsea will be ending the season in top 4, their performance has dropped, and other teams fighting for the same spots are kind of better than them, but we shouldn’t conclude yet, this is football. It’s only two clubs that I know that top 4 is assured for which is Liverpool and Arsenal, nobody knows the team which will be securing the third position, and fourth position, because the points difference between clubs fighting for the two positions is just so close, so nobody knows the club which will end up securing it.