The striker put the ball in the net with the scoreline tied at 1-1, only to have his goal ruled out due to an alleged handball offence.
However, the Zenit star is adamant that the ball hit him on the shoulder when the cross came in.
"To me, it was clean. I controlled the ball on my chest and shoulder," he told Rede Globo. "I saw the ball go in but he didn't give it and I initially thought [that the linesman] had given offside.
"But the important thing is really that we still made it [through]. In times like this we see the strength of the group; how much we support each other."
Brazil won the match 3-2 on penalties after it finished 1-1 after extra time. They will now play Colombia for a place in the semi-finals.