Aguero headed City's winning goal to book an FA Cup final meeting with Wigan next month but the striker also left his mark in another way, jumping on Luiz in a manner that would surely have led to his dismissal had referee Chris Foy seen it properly.
But Benitez was more frustrated at Foy's failure to spot City skipper Vincent Kompany grabbing Fernando Torres in the box."I don't like to point at players in this kind of situation," said Benitez of Aguero's second-half tackle. "For me, the main one is the penalty not given. The consequence could have been a red card and a penalty. It could change the game."
He added: "Yes (they got it wrong). It is something they have to clarify. I have seen the pictures. Kompany has the shirt."
As City boss Roberto Mancini was adamant Yaya Toure should also have had a spot-kick, the incident involving Aguero was more significant.
It is unlikely the South American will face restrospective action as it occured within a Luiz challenge that meant even the Brazilian wasn't exactly sure what had happened.
"Many people have said to me about this tackle. I didn't see it because I was on my back," he said. "I felt it a little bit.
"Sometimes in a game people have five seconds when they are angry and do things they don't like to do. I think it was that.
"I never saw Aguero do a bad tackle on other players. It was five seconds of anger and I forgive him."