The Rabbitohs made the tri-colours pay immediately, a sweeping backline play had South Sydney fans feeling deja vu as the left-side shift was executed like a training drill, and Alex Johnston touched down for his 29th try of the season.
Latrell Mitchell slotted from the sideline to lead 6-0.
A poor kick following points had the Roosters back on the attack, with a crucial six again call handing the Chooks field position that they refused to waste.
Sam Walker couldn't add the extras, leaving South Sydney with a narrow 6-4 advantage.
A dubious six-again after a bat-back from Joseph Suaalii handed the Roosters a full set ten metres out from the Rabbitohs line, and it took just one play to turn the chance into points after a 30-metre pass from Sam Walker put Daniel Tupou over in his 22nd finals game.
Walker again went wide, however the try was enough for the Roosters to lead 8-6 over their arch rivals.
The game returned to a heavy-hitting arm wrestle after Radley returned to the pitch, however the pendulum swung quickly after a high tackle from Thomas Burgess on James Tedesco marched them up up field.
Tedesco was forced from the field following the knock with a Category Two concussion, and despite the Roosters bench being told he would return, the Blues captain later failed his concussion test and wouldn't return.
A second high tackle from Burgess saw him sin binned in the 16th minute, and Taane Milne joined him soon after, clipping Suaalii around the chops and leaving the Rabbitohs two men down after just 17 minutes of the contest.
The Roosters failed to capitalise on the numerical advantage, Angus Crichton's drop ball compounded by a penalty, handing the Rabbitohs handy field position despite being outnumbered.
Despite the constant overlap, they managed to find Latrell Mitchell again on the sweep, the former Rooster holding the ball and backing himself against the defence, pushing off defenders to touch down and hand the Bunnies the lead again.
He converted his own try to lead 12-8, despite still being down two players while the Roosters enjoyed their full complement.
The Roosters couldn't score during their ten-minute advantage, leaving South Sydney leading 12-8 when it returned to a 13-on-13 contest.
The second half picked up where the first left off after Siosiua Taukeiaho left the field concussed following a head clash with Hame Sele, playing the ball sideways before being escorted from the field.
The Rabbitohs made the Roosters pay minutes later, a strong run by Campbell Graham through the middle giving them a roll, before Cam Murray found Cody Walker on the left, cutting out the rest as Johnston touched down for his second.
He's now the only player in history to score 30+ tries in two consecutive seasons.
Latrell slotted it from the left touchline to lead 18-8.
Both Matt Lodge and Jared Warea-Hargreaves were placed on report in the ensuing minutes, the latter sin-binned for a head slam on Burgess in the 48th minute, becoming the fourth player to sit during the game.
The score board continued to tick over minutes after JWH's brain snap, Jai Arrow crossing for his second try of the season off a perfectly weighted grubber from Cody Walker, Mitchell extended the lead to 24-8.
The game set a new NRL record in the 60th minute, with Junior Tatola and Victor Radley both binned for their role in a push-and-shove, Tatola giving a Rooster's players a facial before Radley ran in, binned for the second time in the contest.
Only desperate goal-line defence would deny Kevin Naiqama a try in the following set.
The Rabbitohs sealed the win after a late try to Isaiah Tass, their left edge singing in comparison to last week's efforts, Mitchell perfect with the boot as the Rabbitohs wrapped up the contest 30-14.
'Glory Glory' echoed around the rebuilt Allianz Stadium for the first time as the club continues their attempts to make it their full-time home ground from 2023 onwards.
There'll be a nervous wait at the judiciary for Thomas Burgess and Taane Milne, who had four high tackles between them, three of them being penalised with a sin-binning, with Burgess' first tackle which concussed Tedesco the only one that was marched.
It was a record breaking match, between Johnston's second-consecutive 30-try season to a whopping seven sin-bins. Even more stunning - five of eight tries were scored by the side outnumbered numerically.
The Rabbitohs march on to a Saturday night semi-final against Cronulla, likely to see them return to Allianz Stadium.