After losing heavily to Chelsea and Liverpool last week, Tottenham completed an unwelcome hat-trick with Dimitar Berbatov scoring with two early headers and substitutes Gilberto and Darren Bent wrapping up the scoring at White Hart Lane.
Ferdinand was to blame for Berbatov's two goals, both free headers from Tom Huddlestone free-kicks.
"He was nowhere to be seen," said Curbishley. "He's got to dig in, he gave a penalty away against Chelsea early in the game and put us on the back foot.
"You can't allow centre-forwards to have free headers.
"Berbatov didn't have to jump. Then straight away there was another one. It's difficult to come back from it."