On-loan striker Radamel Falcao still needs to prove himself at Manchester United, according to the club's manager Louis van Gaal.
The Colombian was left out of the matchday squad for last Sunday's 1-0 defeat to Southampton and has struggled to justify the sizeable sums United have spent on him.
The Monaco-owned frontman has scored just three times in all competitions for United, having been in and out of Van Gaal's side, and the Dutchman has challenged his striker to prove his worth.
"We have agreed that we have made this deal and everything is clear. It is not the end of the year so he has the chance [to prove himself]," Van Gaal told reporters before addressing the potential of further arrivals this month.
"The quality in his performances and matches, he has to compare. You have a game plan and I already explained that [after the Southampton defeat].
"If a player cost £95 million or £5,000, it is not any different.
"A player of £95m has to prove himself also. If I am not like that, maybe he has less motivation. But I have to be like that.
"I don't think we shall be very active because all the players of a certain level are not available.
"I have said before that when we buy a player he has to be better than our players playing now and that is a difficult job."
With Robin van Persie a doubt for Saturday's trip to QPR, Falcao could return to the squad as United seek to bounce back from their Southampton setback.
United failed to muster a shot on target in that loss but Van Gaal remains confident his side can regain a top-four place in the Premier League this season.
"That is our goal and that I have always said, even in the beginning," he added.
"We want to be champion, but then you have to win matches against Southampton and Aston Villa away.
"When you are not doing that you cannot be champion. At this moment we have played 21 matches and we are in the area of the four.
"We have to fight for it because a lot of other teams are willing the same goal."
