Jeronimo, whose 23rd-minute cracker was worth the admission price alone, was joined in the goal fest in quick succession by last week's hat-trick man Sergio Cirio in the first half and Fabio Ferreira in the second.
Kenny Cunningham got one back for the Phoenix when he rifled home a beauty before United substitute Awer Mabil responded with one final dagger at the death.
Wellington, fresh off a fine 4-1 away win against Central Coast but with a season-long propensity to leak goals, were thoroughly dismantled by the Reds, who bounced back into third spot on the ladder, for the time being leapfrogging last week's conqueror Melbourne Victory and Sydney FC.
The visitors were reduced to 10 men when Manny Muscat was given his marching orders in the 73rd minute when he copped his disqualifying second yellow for hanging onto Jeronimo, but the extensive damage had already been done.
United looked red-hot from the outset, with Jeronimo leading the charge.
The Argentinean spearhead forced Phoenix goalkeeper Glenn Moss into a low save in the third minute before zipping past tall centre back Michael Boxall in the ninth with some fancy footwork, Jeronimo's low skidder again denied by the Wellington gloveman.
Two minutes later, Isaias curled one from just inside the 18-yard box which was athletically denied at full stretch by the diving Moss.
The Reds were switched on and setting a cracking pace, the Phoenix custodian equally up to the task, as was Adelaide keeper Eugene Galekovic, who stymied a miscued shot from Belgian striker Stein Huysegems, forced on to his non-preferred right foot.
Moss was no chance whatsoever in the 23rd minute when Jeronimo scooted past Boxall and slotted a goal for the ages.
Cutting forward with style, Jeronimo, on the second touch and with supreme control and power, unleashed a stunning volley from range past Moss to stun the visitors.
Then in the 29th minute, Cirio doubled Adelaide's lead and notched his fourth goal in his past two matches when he calmly steered one from the penalty area after being brilliantly teed up by Ferreira's fine cross.
Cutting through the Phoenix defence in the 44th minute, Ferreira was brought down inches outside the box by Manny Muscat, who was duly booked.
Michael Zullo's cracking free kick slammed into the post, the Reds still with all the momentum and a sizeable cushion at half-time.
Cirio was crunched heavily by Muscat in the middle in the 55th minute, the Spanish star limping to the sideline holding his neck and eventually subbing out of the contest, but the Reds remained otherwise unstoppable.
Ferreira, fed beautifully by Tarek Elrick, registered his seventh goal of the season with a one-touch rifle that smashed the top left-hand corner of the net in the 59th, on any other night a strong contender for goal of the game.
Then three minutes later, the Portuguese winger had his third score involvement when he delivered a perfect cross to Jeronimo, who hammered it home to rapturous applause.
Cunningham's 67th-minute bullet from long range was a beauty, too good for Galekovic but only met with restrained celebrations such was its futility.
With one last salvo, Jeronimo's crack at a hat-trick in extra time beat Moss's clutches, bounced off the post and into the lap of Mabil, who completed the massacre with the easiest of tap-ins, coupled with a celebratory jig to cap a blistering and persistent Adelaide barrage.
