Louis van Gaal has admitted his side must focus on the fight for Champions League qualification ahead of their trip to Queens Park Rangers on Saturday.
United had been touted as potential title challengers during their 11-match unbeaten run over the Christmas period but are now 12 points behind leaders Chelsea.
The Red Devils will leapfrog Southampton, who beat United 1-0 last week, into third place with victory of Harry Redknapp’s side but Van Gaal admitted the defeat was costly.
“We want to be champions, but then you have to win matches against Southampton and Aston Villa away,” said the former Netherlands manager.
“When you are not doing that you cannot be champions.
“Our goal from the beginning was that we start a process to be within the first four because we want to play in the Champions League, and that is still our goal.”
Despite the Hoops sitting second bottom of the Premier League, Van Gaal is predicting a tough game against a team who have lost just twice at home all season.
All 19 of their points have been registered at home and in Charlie Austin, December’s player of the month, they have a striker who will punish any defence mistakes.
“I think their players will do everything to beat Manchester United. Every player and every team wants to beat Manchester United,” added the 63-year-old.
“QPR have a playing style that is difficult for us, we have seen that already.
“They play a lot of long balls, they have strong strikers and we have to beat them in spite of that.”
United will have to do that without joint top scorer Robin van Persie, who is set to miss the game with a minor injury.
Radamel Falcao is likely to return to the starting XI after missing out on the squad against Southampton, and his manager has challenged him to prove his worth.
The Colombian, who earns £265,000 a week, has scored three times for United this season but parent club AS Monaco will only sell if his £40million buy-out clause is matched.
“If a player costs £95million or £5,000 it does not make any difference, you still have to prove yourself,” said the United manager.
“We have made this deal and everything is clear and it is not the end of the loan so he has the chance for that.”