Ralf Rangnick admits his Manchester United stars need to improve their mental strength to salvage something from their season.
United have gone three games without a win to lose vital points in the race to finish fourth and secure Champions League qualification.
The fallen giants have taken the lead in their last two Premier League games, only to allow rivals to come back to earn draws.
Rangnick reckons the problems United are suffering have got into the heads of his stars and the German coach, who has drafted in a psychologist to help his squad, said:
"The situation is clear. In 11 out of 13 games we scored the first goal, but didn't win any of them. It has cost us points in the league and a place in the FA Cup.
"It's about doing it for the entire game. This is the next step we have to take. To raise our level, stay focused, because we've given away goals too easily and it was our own mistakes we made that allowed those teams to score.
"If we are not winning the games it effects the minds of the players. They are not robots, they are human beings. We need to kill the game off. Score a second and third goal."
United dropped to fifth in the table following last weekend's draw with Southampton and Rangnick admits the best his side can hope for this season is to finish one place higher.
Rangnick, who will be without the injured Edinson Cavani for Tuesday's clash with Brighton, added: "We need to want to finish 4th in the league. This is the highest achievement we can get. That's our ambition and what we are aiming at.
"Next season, I know what it will take (to challenge for trophies), but it's not the time now to discuss this. My focus is on the next games, the current squad and getting the best out of this season."
