Aguero scored City's winner in their 2-1 Wembley triumph But his second-half challenge on Luiz left a sour taste as he jumped on the Chelsea defender's back.
And while Luiz did not condemn Aguero, he did claim if the striker had done something wrong, he should be big enough to admit it.
"Aguero's a great player," Luiz said. "He needs to be honest with himself and say I don't like to do bad tackles.
"People are happy when Aguero scores goals and does good things in the game. Many kids see the game, watch the game and they want to see good things and not bad things.
"I didn't see it because I was on my back but 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," he said. "I never saw Aguero do a bad tackle on other players. It was five seconds of anger and I forgive him."
The South American will not face retrospective action, the Football Association announced Monday.
Coming just 24 hours after the ugly scenes involving fighting Millwall supporters that scarred the other semifinal, it was a vision football could have done without.
"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 said. "Yes [they got it wrong]. It is something they have to clarify. I have seen the pictures. Kompany has the shirt."
Manchester City manager Roberto Mancini said he had not seen the incident, even though it occurred right in front of his dugout.
"I need glasses," he said, sarcastically.
"If I saw I would say I saw. I don't know what he did but usually Aguero takes a lot of kicks from the defenders," he said. "The referee was there. There are six referees. If Sergio did something wrong ..."
Information from Press Association was used in this report.