Fulham goalkeeper Edwin van der Sar believes goalscoring problems could deprive Jean Tigana's team of a European place this season.
They are 10th in the league and may only need to finish three places higher to qualify for Europe.
But although Fulham have kept clean sheets in five of their last six Premiership games, Van der Sar is concerned they have only scored two goals in those matches.
Strikers Louis Saha and Barry Hayles have been unable to reproduce their prolific form of last season when they scored 51 goals between them.
The Frenchman has only one league goal since August and Hayles's seven Premiership goals have not been enough to compensate.
On Sunday they face Manchester United at Craven Cottage and Dutch international Van der Sar said: "It is possible to get a European place but I think it is going to be hard.
"The lack of goals is a problem for us. I don't think the team have moved on a great deal since we played Manchester United at the start of the season.
"We played better in that game than we have in the last couple of matches.
"So we have to put everything aside to get a good result against them."
Fulham went to Old Trafford in their first match of the campaign and lost 3-2 after twice going ahead. Saha scored both their goals and looked as if he was going to take the top flight by storm.
But he has suffered from a lack of confidence since and has left manager Tigana hoping £11.5 million striker Steve Marlet not only recovers from a fractured leg on schedule in January, but that he immediately finds form.
Van der Sar, 31, added: "After we played United it did not look like we would have the problem scoring goals we have had.
"Sometimes we miss chances too easily. Against United it was a good start. But it is important in games against lower teams and our closer rivals that we also score a few goals."
United have recovered from a run of consecutive league defeats against Arsenal, Chelsea and West Ham to win their last four Premiership matches.
One of the main reasons for their revival has been £19m summer signing Ruud van Nistelrooy, who has scored 18 times for United this season.
The Holland striker is a friend of Van der Sar from their time in the national squad and the goalkeeper said: "Ruud has been on fire in the last few games - maybe Ferguson could give him a rest on Sunday.
"United have got back on their feet in the last couple of weeks. You cannot lose the quality they have with a few bad results.
"I played for big clubs Ajax and Juventus before I came to Fulham and we had poor periods of five or six games but when you have that sort of quality you always bounce back."
Fulham midfielder Lee Clark has a calf injury and is unlikely to recover before Sunday.
United manager Sir Alex Ferguson has no new injury worries and midfielder Paul Scholes is available again after suspension.