Brad Shields scored two tries to help Wellington edge Southland 30-25 in their ITM clash at Westpac Stadium on Thursday.
The result sees the Lions climb off the bottom of the Premiership standings and move one point ahead of the Stags, who had to settle for two bonus points.
In the battle to avoid relegation, Southland outscored their hosts by four tries (including two for Matt Saunders) to three but it was a near flawless goal-kicking display by home fly-half Lima Sopoaga that proved to be the difference between the sides.
Sopoaga landed six of his seven attempts at goal while visiting kickers James Wilson and Robbie Robinson had poor nights with the boot in wet and windy conditions.
Southland's set piece was the origin of their down fall as Wellington ruled in both the line-outs and scrums.
Wellington led 13-10 at half-time and their scrum dominance was telling in the second period as Shields forced his way over twice in the final quarter.
Replacement Marty McKenzie's late penalty saved a second bonus point for the Stags which could prove vital in the run-in.
Tries: Stewart, Shields 2
Cons: Sopoaga 3
Pens: Sopoaga 3
Tries: Bekhuis, Saunders 2, Koonwaiyou
Wellington: 15 Apoua Stewart, 14 Alapati Leiua, 13 Conrad Smith, 12 Charlie Ngatai, 11 Julian Savea, 10 Lima Sopoaga, 9 TJ Perenara, 8 Brad Shields, 7 Scott Fuglistaller, 6 Dean Brunsdon, 5 Mark Reddish, 4 Jeremy Thrush (c), 3 Neemia Tialata, 2 Dane Coles, 1 Reggie Goodes
Replacements: 16 Motu Matu'u, 17 Jacob Ellison, 18 Joe Latta, 19 Faifili Levave, 20 Frae Wilson, 21 Michael Hobbs, 22 Steve Honey, 23 Arden David-Perrot.
Southland: 15 Robbie Robinson, 14 Kade Poki, 13 Kendrick Lynn, 12 Matt Saunders, 11 Glen Horton, 10 James Wilson, 9 Scott Cowan, 8 Elliot Dixon, 7 Tim Boys, 6 John Hardie, 5 Ben Nally, 4 Josh Bekhuis, 3 Nic Barrett, 2 Jason Rutledge, 1 Jamie Mackintosh (c).
Replacements: 16 David Hall, 17 Chris King, 18 Michael Fatialofa, 19 Tom Chamberlin, 20 Sonny Rangitoheriri, 21 Marty McKenzie, 22 Tony Koonwaiyou, 23 Michael Peterson.