The five-time champion trumped Phys Ed A in the final of the pre-season tournament at the Edgar Centre on Tuesday night.
In a rematch of last year's final, Southern won a closely contested game 30-29.
It was a result that bodes well for both teams as they head into the first round of the season on Saturday.
The third-fourth playoff also proved to be a tight contest.
In that, College Men edged University Albion 24-23.
Earlier College Men had fallen to Southern Magpies in the semifinals, while University Albion went down to Phys Ed A.
College A was fifth, while Phys Ed B claimed sixth spot.
Southern Tui managed seventh, while University Albion came in eighth, St Hilda's Collegiate was ninth and Premier B grade teams Phys Ed C, College B and Phys Ed Blue filled the final three places.
The club season begins on Saturday, with the premier A grade back to the weekend after being played midweek last year.
University Albion A opens the season at 9am against Southern Tui.
College A will then play University Albion B at 10.45am.
Southern Magpies gets its season under way against Phys Ed Blue at 12.30pm, while Phys Ed A plays St Hilda's at the same time.
