The night belonged to Southland forward Leon Henry, claiming a double-double with 19 points and 13 rebounds, of which 10 were defensively.
Import Brian Cronklin chimed in with as many points but was one rebound shy of a double-double.
Their small men were equally adept, Reuben Te Rangi contributing 15 points and claiming seven off the boards.
For the Saints, guard Corey Webster top scored with 19 points and eight rebounds while forward Casey Frank managed 18 points and nine off the board.
That import Rick Rickert added only 12 points and claimed seven rebounds was a testimony to tight marking from Southland, with ex-New Zealand Breaker Kevin Braswell aptly marshalling the troops.
Effectively, Final Four playoffs night isn't show time but making one's lay ups as some players looked guilty of trying to look pretty for the Sky TV cameras when going up for shots.
Wellington often looked like sleep walking but whatever coach Pero Cameron said in the locker room at halftime worked as they as responded in the next quarter, reducing the deficit to four points as Frank and Webster cranked it up.
A couple of "And ones" later and the Sharks were back to a 10-point lead as Southland went up a few notches to close out the unexpected win.