United's Under-19s lost out to Group A leaders Real Sociedad in the UEFA Youth League after Alvaro Odriozola's early goal proved decisive.
The Reds have three points from three matches and face an uphill battle to qualify for the knockout stages of the inaugural competition with a positive result probably required in San Sebastian next time out. Ben Pearson's injury-time red card only added to the frustration.
Swiss signing Saidy Janko made his United debut at fullback for coach Nicky Butt.
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball