Louis van Gaal has said he did not approve of some Manchester United supporters booing Marouane Fellaini when the player was substituted in the 1-1 FA Cup draw against West Ham at Old Trafford.
Fellaini, who had been brought back into the side for the 2-0 Europa League defeat to Liverpool on Thursday after injury, was substituted after 76 minutes against the Hammers.
Van Gaal, who had praised the Belgian after the Liverpool game, said: "That was disappointing [the booing], but that was the only moment I was disappointed with because they [the fans] were supporting our side in spite of two losses this week.
"Maybe they have another opinion to me. I think Fellaini played a good match again. He performed well in our gameplan."
Fellaini's replacement, Bastian Schweinsteiger was singled out for praise by the Dutchman, who changed his team's fortunes with the introductions of the German midfielder and winger Memphis Depay.
"I think he did fantastically, but of course he played 15 minutes," Van Gaal said. "Ninety minutes is different, but I was very happy with him."