Inevitably they have to do that if they can't make Sociedad step down from his current position.
Their first game did not go well for Manchester United and indeed one of the last hopes is with the second meeting later.
The problem is will they be able to? because in the first match by playing at Old Trafford they had to feel defeat.
If the question you ask must be answered, then I will try to give a few answers that may be logical for you to think about. If Manchester United doesn't have the ability to get a win against Real Sociedad, it's actually not a big problem because Manchester United's position itself is very safe and only needs one more win in the two remaining matches in the group stage.
But when it comes to ability in general, I don't think Manchester United would have made it this far if they didn't have the ability. Now, look at Arsenal, which was beaten by Manchester United this season in the Premier League, which basically never occurred to many people, including me.