Hooker Andrew Makalio opened the scoring for Tasman inside 10 minutes from a lineout drive, but was swiftly answered by Southland loose forward Tony Lamborn. After some solid defence at one end, the Stags found the lead through hooker Flynn Thomas.
For a moment, it looked like Southland might have been on their way to ending a 13 match losing streak. But the Mako put that idea to bed before halftime with back-to-back tries to lead 19-12 at the break.
From there, the hosts never took their foot of the gas as they run in another four tries in the second 40 minutes – including a brilliant solo effort from Will Jordan in the dying stages – to close out a 21-point win and make it two from two.
Auckland took a similar route to beat Northland in Whangarei, but were able to walk away with a comfortable 28-12 win.
Northland started the evening strong at both ends, with Rene Ranger leading the way in setting up Blake Hohaia for his side's opening try, before going in to score the second himself.
It was a strong second half performance that proved the difference for Auckland, who trailed 12-7 at halftime - getting on the scoreboard through Harry Plummer.
The side ran in three unanswered converted tries, which included a double for winger Melani Nanai, to seal their second win in as many matches as Northland were slow to get back into the match after the break. Auckland ran in their three tries within 11 minutes of returning to the pitch for the second half.
Tasman and Auckland now sit first and second on the Premiership ladder respectively, each on nine points and one bonus point ahead of North Harbour, who are also unbeaten in their opening two fixtures.
Tasman 45 (Quinten Strange 2, Will Jordan 2, Andrew Makalio, Solomon Alaimalo, Ethan Blackadder tries; Tim O'Malley 5 cons) Southland 24 (Tony Lamborn, Flynn Thomas, Manaaki Selby-Rickit, Rory van Vugt tries; James Wilson 2 cons). HT: 19-12
Auckland 28 (Melani Nanai 2, Harry Plummer, Salesi Rayasi tries; Plummer 4 cons) Northland 12 (Blake Hohaia, Rene Ranger tries; Jack Debreczeni con). HT: 7-12