The scoreline was bad enough, but Henrique Viana, who had shrugged off an injury from last week to play, was again injured in the 24th minute and ended up in Dunedin Hospital, where a fracture was confirmed.
The Brazilian ended up in plaster and will not play again for eight weeks.
Fellow striker Peter Rae lasted longer but was also hurt, and his 64th minute exit reduced United to 10 men, since the full complement of substitutes had been used.
It was the second week running coach Uehara's team had to play out the last half hour a man short.
But there was no fairytale ending this week, as Hawkes Bay maintained its feisty start while Southern never got out of first gear.
Barely recognisable as the team that beat Waitakere, Southern looked lethargic and paid the penalty as Hawkes Bay's Sean Morris crossed for an unmarked Aaron Jones to launch a diving header past keeper Tom Batty and after 18 minutes the score was 1-0.
Sloppy marking, especially at corners and free kicks allowed coach Chris Greatholder's side to score regularly in the 30th, 64th, 72nd, 84th and 93rd minutes.
Southern's confidence evaporated as the game progressed, and goalscoring chances that might have stopped the rot were not taken, as the normally reliable Jacob Schneider shot over the crossbar, and similar efforts by Nick Hindson and Dan Morris went astray.
In contrast, Hawkes Bay played patterned football which created space, and some elusive running by Nat Hailemariam teased defenders and his two-goal haul was well deserved.
Southern's consolation goal was a solo effort by Taylor McCormack who badgered Bay's tough captain Bill Robertson into error, then held off challenges before sliding his shot past the advancing keeper Richard Gillespie in the 67th minute.
Bay's last goal also drew a ripple of applause from the disappointingly small crowd, as former Otago player Harley Rodeka laced in a superb goal from 25m.
Greatholder was delighted with his team's controlled performance.
''After a tough week, where we lost three points due to fielding an ineligible player, this result is good and positive,'' he said.
'' We have had some good spells this season, but today was our best two halves, with all players hitting good consistent form that has put us back in contention for a top four finish.''
A philosophic Uehara admitted his side started too slowly, and never reached last week's heights.
''They are still a young side, still learning, and today our luck deserted us with injuries, and having to play for quite a while with only 10 men against a Bay side which was impressive.''
''We are all concerned for Henrique who will be out for a while, but football is all about doors opening and closing.
''There are opportunities to stake claims for a first team place, and we have players keen to do just that.''
ASB Premiership
The scores
Hawkes Bay 6
Southern United 1
Halftime: 2-0
