Cardiff assistant boss Terry Burton admitted mistakes at both ends of the pitch cost them after the 2-0 defeat by Nottingham Forest.
Goals from Lewis McGugan and substitute Dexter Blackstock knocked City off top spot while England striker Jay Bothroyd spurned two glorious openings.
"There are a couple of reasons why we lost and they can be found at both ends of the field," said Burton.
"In a tight game you have to take your chances and we didn't do that.
"Then we gave away two soft goals and that is a recipe for defeat."
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