The new coach of the national team wants the future of the team captain to be taken off the agenda after weeks of debate about his role in the new set-up
Neill's place in the side, as well as his captaincy, was the major talking point in the lead-up to Tuesday's 1-0 win over Costa Rica in Postecoglou's first game in charge.
The 35-year-old was solid at the back against a Costa Rica side missing their main strike weapons up front.
Asked if the captain's performance was enough to secure his place on the plane to Brazil for next year's World Cup, a frustrated Postecoglou urged the media to move on.
"It's not about securing spots and hopefully if nothing else we can stop talking about Lucas Neill," Postecoglou fired.
"To be fair to Lucas he's handled himself really well, I would have probably spat the dummy a lot earlier than this week.
"At the end of the day today was about the group and he led and he had some willing leaders next to him.
"I think the whole group showed this week we've set a standard and moving forward it's going to be really competitive for everyone to get in this squad.
"The 22 guys that worked this week are going to be hard to dislodge and people outside the squad are going to have to show good form to get in here, that's the kind of standard we want.
"We want to be making sure we're not giving away caps or representative honours from now on, we want people to earn them and certainly the 22 that contributed this week earned their spot."
Meanwhile, Postecoglou believes he may have found a long-term solution at left back with Jason Davidson and was also full of praise for right back Ivan Franjic.
"He (Davidson) was fantastic tonight ... he's a young left back who's playing in the Dutch first division (for SC Heracles Almelo) and for a country that's been crying out for a left back he's definitely showing great promise, and he'll get better and we'll give him the confidence," he said.
"I thought him and Ivan were immense tonight as fullbacks.
"We analysed Costa Rica and their strengths are down the flanks, they love to get their fullbacks forward, they love to isolate the opposition fullbacks.
"And I thought those two were just brilliant tonight in not getting beaten and then going the other way proving dangerous themselves."
The coach added of his decision to go with Mat Ryan in goal ahead of Mitch Langerak: "There wasn't much between them, they were both outstanding at training.
"I guess Maty's being playing a little bit more regularly and the way we want to play he's just so good with his feet and he's so good coming off his line that I decided to go with him.
"The original plan was to give Mitch some time but we had some injuries so that sort of disrupted our substitutions.
"But they're two fantastic young goal keepers and I know they'll be pushing each other not just for this World Cup but beyond and neither of them will be able to get complacent as number one knowing the other one is breathing down his neck."