The Blues were beaten 2-1 by City, after Samir Nasri and Sergio Aguero scored either side of the break, before Demba Ba got one back but Benitez feels there could have been more to the game if referee Chris Foy had have penalised Vincent Kompany for a blatant foul on Fernando Torres in the area.
"For me, the main one is the penalty not given," he said.
"The consequence could have been a red card and a penalty. It could change the game.
"Yes (they got it wrong). It is something they have to clarify.
"I have seen the pictures. Kompany has the shirt."