Manchester - Louis van Gaal, the Manchester United manager, has said the criticism being levelled at the club this season could be having a negative effect on his players' performance.
United are in the quarter-finals of the FA Cup after winning at third-tier Shrewsbury on Monday, and will play West Ham at Old Trafford next month.
However, they have lost seven Premier League games so far this season -- the latest at Sunderland, threatened by relegation, last weekend -- and are now fifth in the table, six points fourth-placed local rival Manchester City, who currently occupy the final Champions League place on offer to English clubs.
Van Gaal has come under increasing fire, with the local newspaper, the Manchester Evening News, among the critics who have called for him to be sacked amid constant speculation he he will be replaced by Jose Mourinho, who has been out of work since being dismissed at Chelsea in December.
His team has also been repeatedly criticised, especially after a 2-1 defeat at Midtjylland of Denmark in the first leg of their Europa League last 32 tie, having been knocked out of the Champions League at the group stage.
Van Gaal, speaking ahead of the return leg against European minnows Midtjylland at Old Trafford on Thursday, said: "I think maybe it can be an influence, because there is a lot of criticism so it can influence them (the players).
"But they have to use their tools to ignore the criticism because that's very important -- not only the criticism of their manager but also of themselves," the veteran Dutch boss added Wednesday.
"That is also a means to prepare yourself always properly. It should not be an influencing subject."
United's battling performance against Shrewsbury, in what had been widely seen as a potential upset, brought approval from van Gaal.
"They showed that (fight) against Shrewsbury but every game is different," he said. "We are human beings also. You are not always in the same shape or form.
"They showed against Shrewsbury that that we can play the football we like to play. We have shown this season many times already that we can do that.
"But the circumstances are not so easy for the players because we have to change the line-up a lot of times and that's not beneficial for team building."
Van Gaal has refused on several occasions to cite United's extensive injury list as a major factor in the team's poor showing.
However, he is currently without around a dozen players, with the list being led by captain and England striker Wayne Rooney (knee) and Germany midfielder Bastian Schweinsteiger, who also has a knee problem.
Defenders Luke Shaw, recovering from a broken leg, Matteo Darmian (shoulder) and Marcos Rojo (shoulder) have also been unavailable, while Adnan Januzaj and Marouane Fellaini are both out with hamstring problems.
Ashley Young (groin), Antonio Valencia (foot) and goalkeeper David de Gea are also out of action.