Moved from his usual five-eighth spot, halfback Benji Marshall scored the first try and set up two more to guide the Tigers to a 16-6 lead at half time.
Marshall and several other Wests Tigers stars came off at half-time, the contest evening up after the break.
The Rabbitohs came back to lead 26-22 before the visitors crossed for two late tries in the final quarter.
In all, Wests Tigers scored six tries to five in front of 5000 fans celebrating at the refurbished Redfern Oval.
Wests Tigers' signing, Great Britain Test forward Gareth Ellis impressed as well.
In other signing news, Souths fans received a double boost on the weekend with Kiwi Test hooker Issac Luke and local utility back Beau Champion extending their contracts until the end of the 2011 season.
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