Shamrock Rovers are facing sanctions after some travelling fans sparked mayhem at the RSC by forcing a nine-minute stoppage in the first-half.
Referee Rob Hennessy took both teams off the pitch after a volley of fireworks rained down on them - and in the stand itself.
Waterford midfielder Anthony Wordsworth was hit by shrapnel falling from the sky - but played on - and medical staff were also called into the away section.
And before the start of the second-half, an announcement over the tannoy said Hennessy would abandon the game if anti-social behaviour continued.
Amid all that chaos, the champions scrambled a late come-from-behind victory with killer goals from Danny Mandroiu either side of Sean Hoare’s decisive goal.
Until those late interventions, John Martin’s opener had Waterford on course for a precious victory that would have pulled them clear of the danger zone.
Instead, they occupy the relegation playoff spot.
Crowned champions a week ago, Rovers might have expected to be the big talking point in Irish football this past week as they basked in their glory.
Damien Duff’s dramatic arrival at Shelbourne put paid to that and he was the only show in town.
But Rovers are back in the headlines alright, just not in the manner the club would have hoped for despite this win.
Before those astonishing scenes, Waterford punished Rovers for comical defending.
Jack Stafford’s deep cross should have been mopped up by Leon Pohls but Lee Grace intervened when trying to meet the dropping ball.
And with the Hopos defender and goalkeeper - making his first league appearance in his third season - all in a flap, Martin headed home.
Four minutes later, the game was stopped as those fireworks were launched from the away end.
Some exploded in the stand itself causing widespread panic while others blew up directly over the players.
When Wordsworth fell to the ground, Blues boss Marc Bircham and others on the bench rushed to his aid.
Gardai escorted at least two Rovers fans from the ground while medical personnel entered the away end, although there was no obvious sign of injury.
After the nine-minute stoppage, Rovers created more chances as they looked to claw their way back into the game.
Greene flashed a shot across the face of goal, Graham Burke was denied by Brian Murphy and the goalkeeper then thwarted Grace.
And when Bircham leathered a ball high into the stands just to kill a little bit of time before the break, the home fans serenaded him with ‘One Marc Bircham….’
But Rovers were tenacious in their pursuit of an equaliser after the break with Dylan Watts - who weighed in with three assists - and Mandroiu pulling the strings.
They got their initial reward with 20 minutes to play when Mandroiu headed home a Watts corner to give the champions a way back in.
They made further inroads six minutes later when Hoare buried Watts’ free-kick to leave Waterford wondering what had hit them.
And they were still trying to figure that out when Mandroiu raced through at the death to snatch a second brace in as many games.
WATERFORD: Murphy; Evans, Halford, Nolan, Stafford; Martin, O’Keeffe, Wordsworth, Patterson; Griffin (Power 71, Tshipamba (Quitirna 56)
SHAMROCK ROVERS: Pohls; Hoare, Lopes, Grace (Murphy 61); Gannon, Watts, O’Neill, Farrugia (Cruise 90); Burke (Abada 87), Mandroiu; Greene.
Referee: R Hennessy
Get the latest sports headlines straight to your inbox by signing up for free email alerts
