Cavani was shown a yellow card on Wednesday night after he unveiled a message to the victims of the Chapecoense tragedy.
He scored a 66th-minute penalty to wrap up the win before paying his respects to the 71 people that died on Tuesday.
Referee Frank Schneider has been heavily criticised for his decision but Cavani jumped to his defence following the game.
He said: "I spoke in English with the referee and he told me it was a nice gesture but that he was obliged [to issue a yellow card] and that it is not allowed to send a message by removing your shirt.
"The most important thing is that I was able to send the message I wanted to send. It was an emotional moment. I was happy for the team."