Marcus Rashford has called on Manchester United players to "be real with each other" after Manchester City condemned them to a seventh defeat in nine games on Wednesday.
Bernardo Silva and Leroy Sane struck for the visitors in 12 second-half minutes at Old Trafford to seal a 2-0 win over United, who remain three points adrift of the top four.
"Today we didn't play like Manchester United," Rashford told Sky Sports. "It's not right. The bare minimum is to work hard and give all for the badge, the supporters, the club and yourself.
"It has been a tough road to get to where we are, to get there and not be putting up the same performances as we were in January is disappointing. We know what's been going wrong - it's mentality and willingness to run for your team.
"Forget the league and top four, you don't lose this game. It's that simple as a Manchester United fan. We never call each other out but we have to be real with each other. It's a matter of trying to improve each other.
"It's more getting back used to doing it on the pitch. They [the supporters] know we can do it. Forget the top four and the Champions League. We have to get to the bottom of it and start playing like Manchester United for ourselves."