The Brazilian hitman netted just 24 seconds into the 2-2 draw between Milan and Barcelona at the Camp Nou.
"As soon as the game kicked off, I saw a gap and I ran at it," he grinned on Mediaset Premium. "Barcelona are a very strong side, so we're perfectly happy with this result.
"It was difficult to play and we wanted to have more time on the ball. At the end, when Antonio Cassano went off, I was too isolated in attack.
"Everyone was tired, but I only played 10 minutes against Lazio on Friday, so I wasn't terribly match fit."