While captain Mile Jedinak is out through injury, Postecoglou confirmed on Monday he would "freshen up" his squad for the huge clash at ANZ Stadium.
Victory over Oman would all but secure Australia’s spot in the quarter-finals ahead of their final Group A match – a clash against South Korea on Saturday.
“We learned pretty clearly at the World Cup that by the third game against Spain we were pretty spent as a group because we relied on a fairly core group of players,” Postecoglou told reporters on Monday.
“And not just for those games but even in the lead up and we don’t want to fall into the same trap.
“We want to do well in all three games and tomorrow night a very important game for us.
“We want to make sure the guys we put out there can maintain the same sort of intensity, tempo we had in that first game.”
The Socceroos boss would not confirm his changes but Mark Milligan is expected to replace Jedinak in the heart of midfield, while Nathan Burns, Tommy Oar and Mark Bresciano may all be given starts.
“We just want to keep the momentum going,” Postecoglou said.
“We were pleased with how things went on Friday night in terms of the performance but we still think we can improve and that’s what we’ll be looking for tomorrow night.
“If we can improve on that first game it will give us a good chance to get the result we want and that will set us up for the third game.”
For that to happen the Socceroos will need to dispose of an Oman side that have troubled them in the past and who pushed South Korea all the way in their first match.
Only a stunning late save from South Korea goalkeeper Kim Jin-hyeon stopped Paul Le Guen’s side from stealing a point in the 1-0 loss in Canberra on Saturday.
“As expected they made it tough for Korea. While Korea dominated the chances and possession you saw right up until the last minute the game was in the balance,” Postecoglou said of Oman.
“They are always a tough opponent for us, we’re expecting no different tomorrow night.
“Like we did with the Kuwait game, we’ve analysed them, followed them very closely for the last six months, got all the information we need and have a fair idea of how they are going to set up and what we need to do to counter-act that.”
Postecoglou revealed Jedinak, who twisted his ankle badly against Kuwait on Friday, was no certainty to return for the final group game against South Korea.
But he re-assured fans the injury is not serious.
“We’ll wait and see how he recovers, we certainly very hopeful he’ll overcome it pretty quickly,” Postecoglou said of his skipper.
“It’s nothing major. We’ve had a scan so there’s nothing significant there. It’s just a matter of letting the swelling settle down and get him back running.
