After Costa Rica's 2-0 win over China put them top of Group C, their hopes of progressing to the second round could hinge on their final group match against Brazil.
Before that, Costa Rica have to face Turkey and Guimaraes admitted that will command his attention.
"We are just thinking about the next game, which is Turkey.
"Then we will think about Brazil," said Guimaraes.
Costa Rica's coach said the win over China reminded him of the 1990 Qorld Cup in Italy when Costa Rica opened their campaign with a 1-0 win over Scotland.
He said: "It's always good to start the World Cup with a victory, just like last time in Italy."
Guimaraes praised the efforts of World Cup debutants China, who made his team work for their win.
He said: "It was a very hard game, we knew China would be strong and organised.
"But as the game developed we knew we would get a chance, and when it came we took it," said Guimaraes of Ronald Gomez's 61st minute opener for Costa Rica.
"Today we played well for certain phases of the match and we know the team can grow from here."