Uili Kolo'ofai led the forwards and Luke Herden provided the impetus for the backs as Southern rumbled to a convincing win at Montecillo.
The Magpies can be accused of being predictable but, when their physical approach leads to a six-tries-to-one victory, they won't be particularly bothered.
Lock Kolo'ofai thoroughly dominated the line-outs and roamed the field with intent, while Herden was his usual destructive self in midfield.
No 8 Cam Goodhue was also in vigorous form for Southern, which dominated the early stages of the game with little reward but scored freely in the second half.
Fullback Craig Snedden scored two tries and added a conversion and a penalty to post 15 points for Southern.
Zingari-Richmond, stung by the late defection of first five-eighth Peter Breen to Alhambra-Union, lacked direction in the backs.
But the Colours fought well up front and tried hard to compensate for their lack of gamebreakers.
Southern 40 (Apelu Alapati, Craig Sneddon 2, Luke Herden, Ollie Spence, Laurie McCowan tries; Sneddon conversion, penalty goal, Hamish McKenzie conversion, penalty goal), Zingari-Richmond 8 (Tim Hanipale try; Matt Gordon penalty goal).
Half-time: Southern 15-8.
Referee: Jeff Grubb.
