Smashed by injuries since February and still missing three of their biggest names, the Rabbitohs went to a 12-0 lead early on Sunday before holding onto win.
The victory did not come easily, with the Tigers appearing to level the scores at 16-16 with five minutes to play when Lachlan Galvin went over on the left edge.
But replays showed the departing Tiger dropped the ball as he dived over the line, before Jai Arrow crossed late to seal the win for the Rabbitohs.
Bennett is renowned as one the greatest coaches in rugby league history, but if he is to keep this Souths side in the top eight it would be among his best feats.
The Rabbitohs finished 16th last year and were only saved from collecting the spoon by a woeful Wests Tigers.
They have then spent the first 11 rounds of 2025 without Cameron Murray, while Latrell Mitchell and Cody Walker have headlined big names to spend time out.
Even on Sunday night at Campbelltown they were still without first-choice five-eighth Walker, centre Jack Wighton and hooker Peter Mamouzelos.
But still, they were clearly the better side, with Keaon Koloamatangi a man mountain in the middle of the field with 329 metres at prop.
Siliva Havili got the Rabbitohs' first when he burrowed over out of dummy-half, before Jayden Sullivan laid on their next.
Effectively on loan from the Tigers and set to return there next year, Sullivan spotted a gap behind the ruck and went 60 metres before Euan Aitken finished the job.
In contrast, the Tigers failed to capitalise on their best chances with Apisai Koroisau playing a lone hand.
On the same night he was again overlooked by NSW for Reece Robson, Koroisau almost single-handedly dragged the Tigers back into the match.
He scored their first when he spotted a gap from his own 30-metre line and broke down field,
The hooker got one-on-one with Latrell Mitchell, feigned a kick, dummied and stepped past the fullback to score while leaving the Souths No.1 falling to the ground.
At 16-6 down Koroisau then got Souths down to 12 men when he burst into a gap from a Terrell May offload and forced a professional foul from Tallis Duncan.
The hooker then made immediate use of the extra man, dummying out of the ruck on the next set and stepping through the defence to score.
But any hope of a Tigers comeback were dimmed by Galvin's error over the line, before Arrow officially killed them off to leave the joint-venture stuck in 10th spot.
May also had a big game for the Tigers with another 199 metres from 19 runs, but it will not be enough to win his way into the NSW team.
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