The Selecao secured their last eight place with a penalty shoot-out win over Chile on Saturday and they will face their South American rivals in Fortaleza on Friday evening.
And although Neymar was on hand to net what proved to be the decisive penalty for his country - with Gonzalo Jara missing Chile's next kick to hand the hosts victory - his manager Luiz Felipe Scolari was furious with the treatment he had had to handle against Jorge Sampaoli's side.
"We have four or five days to get Neymar in shape for the next match. It is a big problem, his thigh is swollen," said Scolari speaking after the game.
"I remember when I was Portugal coach and, in the fifth minute of the game, Netherlands defender Khalid Boulahrouz broke Cristiano Ronaldo in half and he had to go off 10 minutes later.
"When I saw Neymar after the game today I remembered that. Some people say Neymar falls too easily. He fell three times."
Midfield destroyer Luiz Gustavo is definitely out through suspension - having picked up a second yellow card of the tournament against Chile - but it is the possibility of losing Neymar which will be a major worry.
The Barcelona man has scored four goals already during the World Cup and has risen to the challenge of leading his country on home soil.
Additionally the 22-year-old already has 35 goals in 53 senior internationals for his country.