It was the tactical decision by ETH that cost Man United the game. Like you said Martial was having the best of game and he was replaced with the ineffective Weghorst.
~snip~
It looks like the draw at Old Traford benefited Sevilla a lot. Their second leg will be played in Spain. Many players are injured and accumulated cards, hoping that Man United can qualify seems very difficult. ~snip~
As the host of the second leg, of course Sevilla is very lucky. In fact, I also read that Rashford is also unavailable in the second leg. It is possible that Sevilla will continue the record of never losing and qualifying for the semi-finals.
Even so, I still have high hopes for Manchester United for the quarter final this time and Ten Hag really needs to provide real direction, especially for United's defenders in the second leg so that mistakes like the first leg can be minimized properly.