Taieri came out firing to score three tries in the first 15 minutes to set up a big win at Peter Johnstone Park.
The home side dominated the first half and scored five tries to lead 29-7 at the break.
It sustained the pressure to score four more tries in the second spell.
Winger Jared Campbell finished strongly to score three of Taieri's tries, and five-eighths Hayden Parker and Andrew Reid had lively games in the backs.
Loose forwards Jeremy Corliss and Kurt Webster were efficient at the breakdown and played key roles in sustaining Taieri's continuity play.
Southern was forced to play catch-up rugby and only started to put its game together in the second spell, captain and prop Warren Moffat leading the way with his strong driving game.
Flanker Simon Knight toiled efficiently and Greg Zampach looked dangerous on the wing but did not receive enough ball.
Taieri 53 (Jared Campbell 3, Andrew Reid, Tom Davie, Hayden Parker, Steve Green, Ricky Stewart, Matt Hogan tries; Reid 4 con), Southern 26 (Harry Uffindell, Lewis Hancock, Ean Griffiths, Mark Sherlock tries; Hancock 3 con).
Halftime: Taieri 29-7.
Referee: Jeff Grubb.
