The Belgium midfielder says the Blues ultimately paid the price for a slow start in their FA Cup semi-final, having shown too much respect for their opponents
Rafa Benitez's side found themselves two goals down minutes into the second half and were unable to produce a comeback despite Demba Ba pulling one back late on.
The Belgium international says the Blues were "frightened" of Roberto Mancini's men in the opening period and that ultimately cost them a place in the final against Wigan.
"We were frightened of City in the first half," he told The Sun.
"We showed them too much respect, and paid the price. Maybe we might have deserved a different fate, but we started the game badly.
"We played the final 40 minutes, but that is not enough to beat City.
"We had chances, and we believed we could do something, but their keeper made some good saves."
Chelsea face Fulham in the Premier League on Wednesday hoping to claw themselves back into pole position in the race for the Champions League.
Rafa Benitez revealed that Ashley Cole will miss the game but is getting closer to a first-team return.
"He will not be back for Wednesday. He is getting closer but not for this game," the Spaniard said.