Roy Hodgson was disappointed with Fulham's defending for the opening goal as they lost 4-0 to Manchester United in the FA Cup at Craven Cottage.
The Cottagers were dumped out at the quarter-final stage thanks to a Carlos Tevez brace and further goals from Wayne Rooney and Park Ji-Sung.
Tevez's first goal came from a corner on 20 minutes when he headed home at the far post after Rooney had nodded on.
He then added the second in the 35th minute with a wonder goal, before Rooney and Park scored in the second-half.
Hodgson believed his side needed to have taken the lead to have any chance against the Red Devils and he was disappointed with the soft first goal they conceded.
Major disappointmentThe Fulham boss said: "I thought we were good in the first half, obviously we were disappointed with the first goal, we know how good they are at set plays so that is a major disappointment.
"The second goal was a wonder strike, then you have a mountainous task. Your only chance against them is to go a goal up."
Hodgson now believes United can complete an unprecedented quintuple of trophies this season.
"Of course it is possible for United to win the lot," he said. "They have a good chance and I wouldn't bet against them. The most difficult will be the Champions League."