Manchester United boss Jose Mourinho says they must prove themselves at Watford on Sunday.
A third defeat at Watford could leave them six points off the title pace after only five games if neighbours Manchester City continue their winning start against Bournemouth.
And Mourinho cranked up the pressure on his players by saying that in return for their lucrative contracts they must be able to motivate themselves for every game.
“I always say that the best motivation you can have is your own motivation,” he said. “You shouldn’t need other people to motivate you.
“I always feel that my job is [to provide] an extra source of motivation but the motivation belongs to the player. The great life, the money they have to do what they want, they shouldn’t need an extra source of motivation.
“Manchester United has to show it in every game and in every competition. The club is too big, the supporters are too passionate, for the professionals not to feel that every game is a very important game.
“So I don’t think they should need a defeat, or in this case, two defeats, to try to give everything they have to give.
“It should belong to them and that is what I expect from them on Sunday – that we will try to win the match normal. The players are professional. They have to be mentally strong.”