Both teams were guilty of coughing up the ball while on attack, creating frustrations for their management as they settled into the game.
Raiders coach David Reedy was happy to get the result but said the process was less than pleasing.
''It was frustrating. Beautiful day - probably don't get much better in the Dunedin winter - and it was one of our worst completions of the season.
''But the boys dug deep. Happy to get the win at the end of the day.''
Outscoring University three tries to one in the first half, South Pacific found the students solid on defence before Jordan Ruatoe made a great break down the right hand flank to open the scoring.
The Raiders' next try came from a well worked backline move that saw Cameron McMillan crash over for another four pointer.
University had good go forward but was struggling to see the space out wide, opting instead to hit up the middle with its bigger men.
Ben McKerchar dotted down for the Raiders to give them a 16 0 lead at halftime.
The second half was a different game for both sides. The Raiders still outscored the students four tries to two but the defensive effort shown by University was a big step up from the first half. University started brightly, with Rob Rietveldt scoring a try.
That was undone by two South Pacific strikes, from vice captain Manassah Kutia and Rema Smith, before the students scored again.
Jordan Tua and Edward Perkins rounded out the scoring for the Raiders.
There was no shortage of feeling in the game with both teams having players come to the sideline to get running repairs, including concussion tests.
Both coaches said there was plenty to work on in the coming weeks but saw positives in the game, as well.
University coach Ray Fitiao said the students had a few things to work on at practice this week.
''We wanted to put on a stronger showing in the second half. But still a couple of those mistakes crept through and we let in a few soft tries,'' Fitiao said.
''We just have to get out there and not let the moment get to us. All things to work on during the week.''
In the other game, the East Coast Eagles beat the Cowboys 26-18 in Invercargill.
By Andrew King.
