Great expectations had fallen flat for Victory in the opening two weeks of the 2012-13 campaign, while the Reds had shot to the top of the table as the only team to win both matches.
But form was reversed on a balmy night in Melbourne, with goals from Mark Milligan and Marco Rojas enough to overcome a Dario Vidosic penalty that briefly put the Reds in front.
Postecoglou had talked tough during the week and his words were reflected on the team-sheet, with six changes to Victory's XI from the side that was humbled 5-0 by his former club Brisbane last Saturday.
Victory's Marcos Flores - facing his former side for the first time since his return to the A-League - ensured the boos sent his way from the travelling Reds fans only increased when he was yellow-carded for his tumble in the area after just seven minutes, but the Argentinian appeared to have a case after Daniel Bowles' challenge.
The hosts had started with purpose, with Milligan adding much-needed muscle in his role screening the defence. Adelaide, meanwhile, appeared happy to sit back and wait for opportunities to appear on the counter.
Victory sought space down the flanks and almost carved out the opener on 10 minutes when Rojas' cross from the right just eluded Archie Thompson in the area - a touch would have meant a goal.
Vidosic was booked for a late challenge on Tando Velaphi on 25 minutes, and the Victory goalkeeper needed to be aware to smother the danger as Reds forward Jeronimo Neumann attempted to run onto a loose ball just moments later.
Iain Ramsay's dangerous ball on an Adelaide counter-attack after 38 minutes drifted across the face of Velaphi's goal, before Victory left-back Adama Traore got a crucial touch to take it out of the path of Fabio Ferreira.
Neumann had two chances as the half wound up, with his second one - an effort he sent skidding wide of Velaphi's right-hand post - particularly close.
Adelaide's bright start to the second half led to the opening goal as Billy Celeski handled in the area and Vidosic made no mistake from the spot.
But the lead was short-lived, with Milligan rising high to emphatically convert Guilherme Finkler's free-kick just four minutes later.
Adelaide defender Nigel Boogaard and Thompson traded efforts - the latter should have scored - before the hosts took the lead on 66 minutes.
Thompson's cross from deep on the right was touched onto his own crossbar by Boogaard, with Rojas stabbing home at the second time of asking after sending his initial header back against the woodwork.
The visitors pushed forward in search of an equaliser, forcing Milligan to fall deeper - making it a back five for Victory - to counter the Reds' raids, but the home side held on.