Australia have a testing start to the final stage of qualifying with the clash against reigning Asian champions Japan in Brisbane shortly after playing in oppressive heat in Muscat.
"I cannot play a team here and go into a qualifier and only have Japan in mind," Osieck said.
"That will never happen, that I will let that slip.
"Oman is like a first final.
"Our focus can only be on this game and the 11 players that will be starting will be the top players for that very moment."
Socceroos captain Lucas Neill required treatment for his groin at training on Wednesday but moved freely after having it stretched out.
Osieck said it was unlikely that Brett Holman would be available for next week's clash in Brisbane with the arrival of his second child imminent.
Japan blitzed world No.92 Oman 3-0 at Saitama Stadium on the weekend but the team from the Middle East is expected to put up a much better fight on home soil.
There is little chance of the Socceroos treating the home side lightly after losing to them 1-0 in Muscat last November.
Osieck believed set pieces would be crucial for Australia with towering striker Josh Kennedy available for the match starting at 5pm local time (2300 AEST).
"I think set plays can be a good weapon," he said.