With the ball on their own 20m line, the Roosters first went out to the left before coming back to the right where Mitchell Aubusson put teenager Boyd Cordner away.
The back-rower toed away and Anthony Minichiello beat debutant Adam Reynolds in a race for the ball to shock the Bunnies faithful.
Earlier, Souths pivot John Sutton looked like he'd be the hero as he scored an individual effort just after the break to give his side an 18-12 lead.
That advantage was increased beyond a converted try when Reynolds added a penalty goal.
The Roosters wasted a bright start from a powerful Lama Tasi try when they went to sleep after conceding a penalty near their own line.
Greg Inglis took advantage with a quick tap to put Michael Crocker over untouched.
While their equaliser may have been given to them, the good fortune gave the Rabbitohs a lift.
Reynolds, having earlier put a kick out on the full, showed his confidence hadn't been rocked when he placed one perfectly for Chris McQueen to reel in for a 10-6 lead.
Daniel Mortimer, who earned his first start for the Roosters after skipper Braith Anasta pulled out with a back injury aggravated in training, matched Reynolds' effort with a pinpoint kick of his own as as Aidan Guerra put the Roosters back in front.
Dave Taylor's questionable tackling technique left the South big man facing another nervous wait after an awkward lifting tackle on Boyd Cordner.
Burgess and Sutton used far more conventional styles to deny Mitchell Aubusson with a try-saving tackle.
- AAP
