Are you then going to conclude that it is the Manchester United goalkeeper Onana that is responsible for the failure they have been experiencing ever since? I doubt if that is the case but let me leave that for now. Back to Chelsea and there possibility of winning this match. I have researched about the last 5 matches these two teams played with each other, that is, Chelsea and Manchester United and from the last match, Manchester united beat chelsea with 4 over 1 at home and before then, they have drawn in the last 4 matches, three of the matches were a 1 - 1 while on the other one it was a 0-0. In all of these, chelsea had hosted the manchester united 3 times whereas Man U have hosted 2 times including the one they scored 4-1.
Judging from the above analysis, one can ordinarily say that Manchester will win this, however, that may not necessarily be the case. Although, Chelsea have not shown that consistency yet, like the Manchester United, but they have shown great performance in their fixtures with Manchester City, Tottenham and Arsenal, recently. This makes me feel like Chelsea has been strong to stand tough matches and either draw or defeat some of those big clubs.
If we talk about comparing these two clubs, just imagine if Chelsea had a striker or midfielder of equal quality to Manchester United, of course Chelsea would probably be much better and I am not here to defend one of these clubs, but from my point of view, Chelsea is actually superior in terms of The thing about readiness to compete in the Premier League is that they just spend a lot of money buying players who are not of high quality so stability is not that good.
For Manchester United, this is just a few mistakes that need to be corrected, it's just that the coach is not wise in dealing with problems even though the players only need a few substitute players to become stronger and on the one hand, several Manchester United players are experiencing injury problems and other conflicts so that their performance is less than optimal.
So these two clubs have their own advantages. If we compare them, maybe I choose Chelsea.