Manchester United legend Peter Schmeichel was left disappointed by their performance in victory over Real Sociedad.
United saw off their Champions League opponents 1-0.
"For the third game in a row they had a good start, but then we saw again the problems they have faced this season. For some reason United stopped playing," said Schmeichel.
"I do not understand why players do this, because it means that the other team is allowed to get back into the game.
"Real Sociedad did not defend well themselves and was not a strong opponent."
