Manchester United manager Louis van Gaal has admitted that he is concerned about the discontent among the supporters, but has once again defended his tactics.
Boos rung around Old Trafford on the final whistle of United's goalless draw against PSV Eindhoven in the Champions League on Wednesday night.
The result means that the Red Devils need to win at Wolfsburg in order to seal a place in the final 16 of the competition.
Van Gaal has been criticised in recent weeks as his team have lacked attacking threat, but the club could move to the top of the Premier League table with a win over Leicester City this Saturday.
"Of course [I am worried about the fans] because the fans have to be happy," Van Gaal told reporters. "You are playing for the fans, so you cannot deny that.
"But also you have to see how our opponents are playing against us, and when you see how they play, you know the difficulty of organising against that type of opponent.
"We are still not lucky in finishing the chances. We are creating chances, and when we are not creating, then maybe I am worried, but we are not giving much away. That is why we are second in the league and second in our Champions League group."
United are just one point behind surprise league leaders Leicester after 13 games.