What Casemiro made was due to Onana's own mistake for passing to the opponent while Casemiro behind him tried to defend by making a tackle, as a result it became a penalty even though the Galatasaray player failed to execute it.
After that they lost their balance in defense to catch Man United defenders off guard, this is even more dilapidated into the Man United squad, Onana with an expensive goalkeeper has a lot of goals if I'm not mistaken after he joined 18 goals into his goal.
Man United's situation in Group A is getting worse, I'm not sure they will make it through if they see this poor performance, Erik Ten Hag has not been able to evaluate as a whole.
I see the Manchester United team as quite sad, as if bad luck always comes to this team from the various mistakes they make which are actually not that important.
Onana is actually a goalkeeper who has quite good qualities (we could see that last season when he was with Inter Milan) but now his self-confidence has really decreased while at Manchester United and his performance in every game is getting worse.
And Casemiro's red card was influential enough that they had to lose in front of their own supporters.
Now that Manchester United have not won any points in 2 matches, of course they will be very doubtful of qualifying from the group.
Actually, I was surprised by Arsenal's defeat, even though they were ahead in the first half, in the second half the Arsenal team experienced a slight decline so they conceded 2 goals, and Lens is a team that has not been good this season. , but they were able to beat the strong Arsenal team. This is an extraordinary result.