Whether a bumper parochial crowd at Bluewater Stadium would have made a difference to the Chris Greatholder-coached side we will never know but, needless to say, the average turnout disappointed the franchise.
"It's a shame. I thought if we get into the semifinals this place would be crammed with people, with both grandstands full and people two to three-deep outside as well so it's disappointing," Greatholder lamented.
Waitakere, he felt, taught them a lesson in how to be more clinical in the attacking third.
The Bay hustled and bustled amid committing fouls out of frustration but the Paul Marshall-coached troops were "quality".
"We were better than them for the first 20 or so minutes," Greatholder said, adding the visitors had gained confidence after scoring against the run of play.
The task in the home-and-away series in the Big Smoke this Saturday just became Herculean with the Bill Robertson-captained Bay needing a four-goal difference to qualify - in soccer parlance that's what fairytales are made of.
"We won't die wondering. We'll go up there to give ourselves as good an account as we can."
The hosts would be "in the dumps" for two days but they have a lot to be happy about after creating history with a maiden playoff in the franchise's history.
Referee Nick Waldron deemed Stephen Hindmarch to have taken out striker Allan Pearce inside the 18m box in the 21st minute.
Golden boot winner Roy Krishna, who silenced the crowd before giving them false hopes of retiring with his trademark hobble, had goalkeeper Richard Gillespie diving the wrong way from the penalty kick for Waitakere to lead 1-0.
The woodwork denied Waitakere another goal a couple of times after Ryan de Vries exposed right back Josh Margetts a few times.
In the 41st Dakota Lucas tapped one in from point-blank range but he was offside to Conor Tinnion's great cross.
Ironically, it was Krishna who brought another deathly silence to the Blues faithful two minutes later, drawing two defenders and Gillespie before pushing the ball casually into the net for a 2-0 lead.
At the start of the second half, Greatholder would have rued subbing Stephen Hoyle for Jarrod Smith who lasted only two minutes before hobbling off.
The coach later explained they went on the word of the medical team but that was "tough luck", falling into the category of other "ambiguities" of suspensions and injuries this summer.
In another flirtatious season to forget, Smith didn't return with Rudi Bauerfeind replacing him.
In the 61st minute, Jacob Butler made it 3-0, nodding the ball in from a corner kick with not a single Bay defender going up.
In the 74th, the tireless midfielder Chad Coombes inflicted more pain to make it 4-0 from a second attempt in the box after a sublime back heel from Krishna.
Cole Peverley brought a muted cheer in the 81st minute with a penalty-kick goal after a defender brought down Tinnion just inside the box.
A beaming Krishna said he was hoping to ply his trade in the MLS in the United States or Ukraine this winter after finding no traction with the A-League.
"I'm working hard but there's nothing on the table here so, hopefully, I'll get a professional club," the 25-year-old Fijian international said.
Two seasons ago he trained with Wellington Phoenix but to no avail.
"They were looking for a target man, someone huge - a No 10 who you can hit long balls to so he can hold the ball - but I know I'm not tall," the class act said with a wry smile of the Kiwi franchise whose coach Ricki Herbert recently resigned.
In the other semifinal, Auckland City pipped Canterbury United 2-1 in Christchurch, as the O-League teams look likely to play in the final in a fortnight.
