"I was hit by two microphones and knocked by a camera on the forehead," he told a news conference. "It's difficult for me because I've only really played in Europe and there the organisation is different."
Ronaldo, who suffered a serious knee injury in February last year, made his debut for Corinthians and played his first competitive game for 13 months when he came on as a second-half substitute in the 2-0 win away to modest Itumbiara in the Copa Brasil.
"When the game finished, I saw a load of people running towards me... Fortunately, the security men arrived. I'm not used to it and I was frightened.
"When I'm on the pitch, I'm concentrating on the game. I can't answer questions when I'm warming up," he said.
Ronaldo added: "I'm happy to have played my first game, it removes a bit of the pressure. But I need to lose a little more weight so that I can be faster and decisive."
