The accurate goal kicking of first five-eighth Tony Fenner made the difference when Southern beat Alhambra-Union at the North Ground.
Fenner punished Alhambra-Union for their infringements and landed five goals from his seven attempts.
The experienced Southern team played controlled rugby and applied pressure and forced Alhambra-Union to make mistakes.
A break down the blindside by wing Joe Hill led to a try by lock Sam Gavigan and gave Southern a 16-3 lead at the break.
A well-executed try by Alhambra-Union No 8 Ben Pereira soon after the break reduced the lead to 16-8.
But more pressure from the Southern forwards forced more Alhambra-Union errors and Fenner added three more penalty goals in the second spell.
A key player in the Southern pack was Gavigan, who was dynamic around the paddock and supplied Southern the lineout ball it needed to control the game.
Loose forwards Andrew Stead and TJ Ioane bustled Alhambra-Union throughout the game and Luke Herden and Blair Polwart were the key to the strong defensive screen in the midfield.
Lock Mitch Ewan had a strong game in the middle of the Alhambra-Union pack and first five-eighth Peter Breen and fullback Tili Puloka were the best of the backs.
- Southern 25 (Greg Zampach, Sam Gibson tries; Tony Fenner 5 pen), Alhambra-Union 13 (Percy Stephens, Ben Pereira tries; Peter Breen pen). Halftime: Southern 16-3. Referee: Anthony Sowerby (Auckland).