Waitakere coach Paul Marshall promised his champion side would take no prisoners, but in the early exchanges, Otago competed as an equal.
Wide on the left, youngster Joel Stevens was on fire, and shocked the large crowd at Fred Taylor Park with a searing run through gaps in the Waitakere defence, and showed aplomb to drill Otago into a seventh minute 1-0 lead.
Stevens (17 ), recently included in the New Zealand under-20 training squad, might have made it 2-0 when he carved past defenders only to be fouled, and the resultant free kick was blitzed into Waitakere's side netting by Tristan Prattley.
The national league is always quoted as a stage on which promising youngsters - especially from the isolated South - get a chance to impress northern selectors.
Stevens did his reputation no harm at all when he again wriggled free, used his pace to get clear and hammered a strong shot against the Waitakere crossbar.
But Waitakere leads the league on merit. Until yesterday it had only conceded one goal and scored 10, and for long periods the Otago defence had a torrid time.
Waitakere midfielder David Mulligan equalised by tidying in a shot by Chad Coombes that Otago keeper Liam Little could not hold, and a disappointed Otago side went in even 1-1 at the break.
The second half had Otago continuing to defend well, with Tim Horner a useful addition to the regular backline of Matt Joy, Thomas Connor, Prattley and Craig Ferguson.
Keeper Little would be disappointed at being beaten by a long shot from Jake Butler in the 55th minute that put Waitakere 2-1 ahead. It was Butler's second long strike in as many matches.
Predictably, Otago coach Richard Murray rang the changes, bringing on Victor da Costa for Sam Mepham in the 58th minute, Regan Coldicott for Aaron Burgess with 20 minutes to go, and Jude Fitzpatrick for Ferguson with 10 minutes to go.
"It's no good defending a 2-1 loss," Murray said, as he encouraged the team to attack in the final stanza.
The logic is impeccable, but sadly there was a repeat of the Auckland match with a late flurry of goals against Otago.
Two goals in the final five minutes by Roy Krishna and Ryan de Vries created a flattering final 4-1 scoreline for Waitakere, and left an extremely disappointed Otago side trudging off at the final whistle.
"The score does not really reflect the match," Murray said.
"We had them rattled.
They were arguing among themselves, and we peppered them with corners.
"Joel scored a top goal and had an excellent game - he was our man of the match - and Tim Horner added stability at the back where we needed it. There were lots of good Otago performances out there. I can't fault anyone."
In other games, Waikato beat Manawatu 3-2, and Canterbury thumped Hawkes Bay 4-0.
In the women's national league, Footballsouth was beaten 7-2 in Wellington.
Chelsea Whittaker scored in the first half, and Sam Muirhead in the second half.
ASB Premiership
The scores
Waitakere United 4
David Mulligan, Jake Butler, Roy Krishna, Ryan de Vries
Otago United 1
Joel Stevens
Halftime: 1-1.
