Cesar said he struggled to keep warm during Tuesday's 2-1 win over North Korea on a freezing evening at Ellis Park.
"I was really cold," said Julio Cesar, who had almost nothing to do until the North Koreans scored their consolation goal in the 89th minute.
The temperature hovered around freezing point and an icy wind did not help warm up the players or fans.
"You do your best, you use a special powder, but when you have nothing to do, it's very bad to play like that, especially in the cold.
"You have to try to keep warm and keep concentrating in case you're suddenly called upon to take part in the game."
CHEAP PRODUCT
Julio Cesar was one of the first players to criticise the controversial World Cup ball, likening it to a cheap product which could be bought at the nearest supermarket.
Like several of his team mates, he also complained that the North Korean rank outsiders were too defensive in Tuesday's Group G match and made it difficult for Brazil to develop their normal game.
Widely considered the world's top player in his position, Julio Cesar said he hoped to avoid joining the growing list of goalkeepers who have blundered in the competition.
"I hope not to concede one of these goals," he said.
"It's an occupational hazard and when it happens in a World Cup, it is magnified and it can be ungratifying.
"But I'm well prepared and I hope in the next six games, I can play well and not make this type of mistake," he said, referring to the number of matches Brazil will play if they reach the final.
He added that it was not all bad news for goalkeepers.
"A lot of goalkeepers are playing well, the Honduras goalkeeper (Noel Valladares) made a really outstanding save against Chile."
