The Stags had a good start, putting the home side under pressure, but once Wellington found their momentum, they ran away with some nice tries.
Fullback Tjay Clarke got the home side under way with a penalty in the 7th minute and Pepesana Patafilo scored the first try soon after.
Flanker Dominic Ropeti was pinged for being offside at a lineout drive, and after an earlier warning for too many Wellington penalties, Ropeti was sent to the sinbin.
They chose to go with a seven-player scrum on their own goal line and the Stags put in a huge shunt and pushed them back.
Semisi Tupou Ta’eiloa scooped up the ball to score.
Caleb Delany extended Wellington’s score to 17-7 at halftime.
Riley Higgins and Highlander Connor Garden-Bachop added another two tries in the second spell.
Stags flanker Leroy Ferguson scored a great try with his forwards rolling him forward and Gabriel Hamer-Webb darted down the side to score again for the visitors.
Replacement hooker Josh Southall scored the final try for Wellington to secure a big win.
In other games in the round, Taranaki beat Waikato 24-10, Northland upset Tasman 32-5, Auckland won the Battle of the Bridge against North Harbour 43-23, Canterbury thrashed Manawatu 68-26 and Counties beat Bay of Plenty 32-19 on Friday night.
NPC
The scores
Wellington 39
Pepesana Patafilo, Caleb Delany, Riley Higgins, Connor Garden-Bachop, Josh Southall tries; Tjay Clarke 3 con, 1 pen.
Southland 17
Semisi Tupou Ta’eiloa, Leroy Ferguson, Gabriel Hamer-Webb tries; Greg Dyer con.
Halftime: Wellington 17-7.
