Chelsea have indeed experienced a lot of improvement after a series of bad results they got at the start of the season, and the draw against Arsenal in the last match is quite clear proof that the Chelsea team is now stronger.
But, for Manchester United, I think they are still not completely out of the problems they are facing now, even though they are slowly getting positive results, but in terms of performance, the Manchester United team has not yet recovered.
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changes that occurred at Chelsea were quite surprising to most people who had criticized this team when it experienced a decline in performance at the start of this season and when playing against Arsenal it was proof that the defensive strength had become stronger and the attack line had become more aggressive than before, but this is all thanks to Pochettino who is still struggling to lift this team to a better place in the EPL standings.
and regarding Man United I really respect your opinion but there is a slight mistake in some of the words you said because if you compare Chelsea with Man United actually these two teams have started to have quite good improvements crawling up from the bottom of the rankings to occupy the top ten positions and you maybe missing something that Man United does not only focus on EPL matches but must focus on UCL matches which gives a slight change to the performance of domestic matches and this makes sense to me.