Portugal need to switch to attack mode against North Korea on Monday to get the big win they may need to open the door to the World Cup second round.
But Portugal suffered a huge blow on Sunday when influential Chelsea midfielder Deco was ruled out after suffering a left hip injury in training.
“Our medical team this morning assessed the Deco situation. He didn't train and he will not be able to play for us against North Korea,” said Queiroz.
With Portugal having drawn their Group G opener against Ivory Coast, and with Brazil still to come, second place in the group was always likely to be decided on goal difference.
But North Korea's battling, well-organised display in their 2-1 loss to the five-times champions has merely made the 2006 runners-up focus even more on finding a way to goal.
“The first game is one in which the team takes fewer risks because naturally they play with an eye on what comes ahead,” said Portugal manager Carlos Queiroz.
“In the second game everything will be much more clear as there is no room to wait. We have to start making things happen and not waiting for them to happen. We have to put our cards on the table and attack.”
Portugal fans and many neutrals will hope a more attacking approach provides the stage for Cristiano Ronaldo to thrive.
The world's most expensive player has not scored a competitive international goal for almost two years, although he went close against Ivory Coast when he smacked a long-range shot against a post.
FIFA rejected Portugal's appeal against the yellow card he got in the first game so he will have to keep his cool in what is likely to be 90 minutes of close attention to avoid another booking and a ban that would rule him out of the Brazil game.
Queiroz is likely to recall Simao Sabrosa after wide man Danny failed to reproduce his lively in recent friendlies.
North Korea earned widespread praise for their work ethic, discipline and technical ability against Brazil and Portugal midfielder Raul Meireles said he expected more of the same.
For North Korea, the prospect of playing Portugal inevitably brings up discussion of the 1966 World Cup.
Rank outsiders, the Asians had already stunned Italy in the group phase when they raced into a 3-0 lead over Eusebio's talented Portugal team in the quarter-finals before the the Portuguese stormed back to win 5-3.
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