Stephen Hoyle scored both the goals in his first start since breaking his cheek in the preseason, but both should have been avoided, Southern United coach Mike Fridge said after the match.
The first came in the 10th minute, when Hoyle got on the end of the corner and hooked it past goalkeeper Tom Batty at the near post.
Fridge was particularly frustrated with the opening goal, because it was almost a carbon copy of one the visitors scored against Wellington earlier in the season.
''We talked about the corners that they could take and what we thought they might try,'' Fridge said.
''And it was so annoying because that is exactly what did happen and they scored from it.''
Despite plenty of encouraging moments from Southern United before halftime, Hoyle doubled his team's advantage in the 55th minute.
Mark Jones sparked the goal with a good run into the box, before pulling it back for Hoyle.
He had time to take a touch before knocking it into the open net, in what probably one of the easiest goals he has ever scored.
''Both goals were very poor from our point of view. It's disappointing when you're conceding cheap goals,'' Fridge said.
Southern United did hit back through Andrew Mobberley in the 61st minute, when his miss-hit strike slid past WaiBOP United goalkeeper Zac Speedy, but the search for an equalising goal went unrewarded.
The best chance went to striker Tom McBride, who came on for Sam Redwood early in the second half, in the 77th minute.
The big striker got on the end of a well-placed corner, only for his header to be brilliantly cleared off the line by Alexis Caramo Varela.
Fellow Scottish striker Sam French went close 9min later, but his left-footed strike was pushed wide by Speedy.
Earlier, Seamus Ryder came agonisingly close to scoring, but his volley from just inside the penalty area was tipped on to the left-hand post.
''I personally think we deserved a point today,'' Fridge said.
''But I thought we tried to keep going right to the end. We had some good chances but just didn't get that little break in front of goal to get the ball into the back of the net.''
The loss means Southern United is seventh in the eight-team ASB Premiership on three points after four games.
Tough games against Wellington in Invercargill and Canterbury United in Christchurch loom before Christmas, but Fridge is not hiding from the challenge.
''If we can just keep that effort and commitment going and catch up on one or two things, I'm confident we can get back on the winning trail,'' he said.
''There is still positives to take from the game, and one of them is that we did have a go at them.''
Fridge is hoping captain Matt Joy does not have a serious foot injury. He took a knock to his foot during the match and will have a precautionary X-ray this week.
ASB Premiership
The scores
Waibop United 2
Stephen Hoyle 10, 55
Southern United 1
Andrew Mobberley 61
Halftime: 1-0
