Fulham always knew the day would come - when their sense of invulnerability would be blown out of the water.
Now they have to prove they have what it takes to bounce back quickly after their first setback since the trip to Everton in early November.
They showed great solidity to go unbeaten in nine Premier League games, but Sunday's uncharacteristically error-strewn performance at Upton Park ended the run.
Howlers from John Pantsil, Paul Konchesky and Dickson Etuhu all led to goals for the Hammers. Boss Roy Hodgson said it was maybe just as well to get all those mistakes out of the system in one go.
Aaron Hughes summed up the mood of deflation in the camp afterwards.
"It was very disappointing. No-one's really too thrilled about what happened. We made the sort of mistakes we haven't been making recently. But we've got to pick ourselves up now and move on," he said.
"We'll sit down and analyse it this week and see the different things where we went wrong.
"We've had a good spell and we've been knocked down, but it's always important to react positively.
"We want to hopefully put it behind us and get back to playing the way we were before.
"We've got a tough game next week at Sunderland as well as the one against Kettering at the weekend to test us."
Match Summary WEST HAM (1) 3 FULHAM (1) 1 Line-up: Schwarzer; Pantsil, Hughes, Hangeland, Konchesky; Dempsey, Murphy, Etuhu (Andreasen 84), Davies (Gera 74); Johnson, Zamora (Nevland 72).
Subs not used: Zuberbühler, Kallio, Baird, Gray.
GOALS: Di Michele (7), Konchesky (22), Noble pen (60), Cole (76). MoM: Carlton Cole