~Snip~
Honestly, both teams are in miserable conditions and their results are bad. Real Sociedad was destroyed by Barcelona lately by four goals, regardless of referees and other factors. Manchester United was just kicked from FA Cup and aren't in a better position..
The only objective factor is playing home for Real Sociedad, otherwise any result could be seen in that game specifically.
There is nothing interesting about the final results achieved by both teams in the last few matches, especially Man United who are currently still having difficulty getting out of a bad situation. Regarding Sociedad's defeat to Barcelona, I can say that it was because they played with 10 men from the 17th minute, if it was an 11 vs 11 match maybe the result wouldn't have been that bad.
In my opinion, the chances are 60% vs 40%, the factor of where they play can make the difference.