Casemiro's game often endangers his own club, it is very unfortunate that the red card really put Manchester United in danger
He sacrifice himself because if he not tackle at that time, the chance Galatasaray will score one more goal is high. Actually he already tried to save Manchester United from defeat as Icardi missed the penalty. But Amrabat making Manchester United lose due to his mistake.
Both of Onana and Manchester United's defenders are playing like shit, it's better to replace all of them.