Goals from Carlo Armiento (2), Bruno Fornaroli and Nick D'Agostino were not enough to prevent Glory from suffering a first defeat of the season as they were edged out 5-4 by Western United in an astonishing game at Geelong's GMHBA Stadium.
Victor Sanchez's early goal saw the hosts lead at the break, but it was during the second half that the game exploded spectacularly into life, with an all-time A-League record eight goals flying in.
Armiento and Fornaroli both found the net in the space of two minutes to put Glory in front, only for Dylan Pierias to strike twice to hand United a 3-2 lead.
3-2 became 3-3 when D'Agostino headed his second goal of the season, before Tomoki Imai fired the men in green and black back in front.
Glory responded yet again, Armiento claiming his second and his side's fourth of the afternoon, but ultimately Steven Lustica's deflected effort six minutes from time decided an unforgettable contest in favour of the Victorians.
While not concealing his disappointment at seeing his side concede five goals, Head Coach Richard Garcia was full of praise for their performance going forward.
"It was a crazy game," he said.
"I thought we did well to get ourselves where we wanted to be early in the second half.
"The little things we did wrong came from our fatigue and we've got to improve on that.
"We haven't had a chance to train [since the Adelaide United game]... and that is something that we've had to adapt to and now we need to put our best foot forward for Tuesday's game [v Melbourne Victory].
"We want to improve on our defending, but we've scored four away from home, so that was pleasing for me and it was pleasing how the boys reacted after a sluggish first half.
"If you tell me that we're going to score four goals away from home every game, I'll be very happy, because there are going to be games where we don't concede five."
Western United fired a warning shot across Glory's bows as early as the third minute when Tomislav Uskok headed Pain's cross narrowly wide.
And it was the dangerous Pain who created his side's opener shortly afterwards, showing great pace to get away down the left before pulling the ball back into the box where Lustica's dummy was followed by an emphatic finish from Sanchez.
Uskok duly went close with another headed effort before Bruno Fornaroli had Glory's first sight of goal, the Uruguayan showing quick feet and great persistence to get a shot away which was deflected over the bar by a cluster of United defenders.
As the chances continued to flow, Alessandro Diamanti played in Besart Berisha, but Glory's old nemesis dragged his shot wastefully wide when well placed.
Despite having been under the pump for much of the opening period, the visitors managed to end it on the front foot, substitute Armiento taking aim from long range and seeing his low shot kept out by Filip Kurto in the home goal.
And it was Armiento who played a key role in Glory turning a one-goal deficit into a one-goal lead inside the opening 12 minutes of the second half.
Firstly, he crashed home a near-post shot after playing a neat one-two with Fornaroli and the former Adelaide winger then returned the favour, whipping in a low cross from the left which Glory's number nine flicked nonchalantly past Kurto.
The men in white barely had time to celebrate, however, as Lachlan Wales got away down the left and picked out Pierias who nodded home to make it 2-2.
And four minutes later, the 20-year-old defender put Mark Rudan's side back in front, this time crashing home a spectacular volley after impressive approach play from Imai.
As the frantic pace of the game continued unabated, Diamanti struck the frame of the goal direct from a corner before D'Agostino lost his marker at the other end of the field and drew Glory level again by heading Kilkenny's free-kick powerfully past Kurto.
A full six minutes then elapsed ahead of the seventh goal of the game which was again created by Wales, his cross eventually falling to Imai who found the roof of the net with a fierce strike to claim his first goal for United.
Once more, however, Glory provided an almost instant response via a Kilkenny free-kick.
This time the midfielder's ball into the box was not dealt with by the home defence and Armiento pounced to angle a shot into the bottom corner and make it 4-4.
Incredibly, the scoring continued six minutes later, this time Diamanti's corner reaching Lustica whose well-struck shot took a deflection on its way goalward and flew past Liam Reddy into the corner of the net.
With time running out, Glory desperately sought to restore parity yet again, but it was not to be as D'Agostino's late header flashed centimetres over the bar.
Western United FC 5 (Sanchez 10', Pierias 60', 64', Imai 75', Lustica 84') Perth Glory 4 (Armiento 56', 78', Fornaroli 58', D'Agostino 69')
GMHBA Stadium, Geelong
Referee: Jonathan Barreiro
Western United FC: 1.Filip KURTO (GK), 2.Aaron CALVER (8.Lachlan WALES 60'), 4.Andrew DURANTE, 6.Tomoki IMAI, 7.Besart BERISHA (5.Dylan PIERIAS 59'), 10.Steven LUSTICA, 11.Connor PAIN, 13.Ivan VUJICA, 20.Victor SANCHEZ, 22.Tomislav USKOK (3.Brendan HAMILL 60'), 23.Alessandro DIAMANTI (c) (27.Jerry SKOTADIS 90+6')
Substitutes not used: 25.Luke DUZEL, 26.Nicolas MILANOVIC, 30.Ryan SCOTT (GK)
Yellow Cards: Uskok, Sanchez, Hamill, Diamanti
Red Cards: None
Perth Glory: 33.Liam REDDY (GK), 5.Jonathan ASPROPOTAMITIS, 9.Bruno FORNAROLI, 10.Andy KEOGH (21.Bryce BAFFORD 65'), 18.Nick D'AGOSTINO, 19.Calllum TIMMINS (15.Brandon WILSON 46'), 22.Josh RAWLINS (37.Riley WARLAND 46'), 23.Dane INGHAM (16.Nick SULLIVAN 78') 24.Daniel STYNES (20.Carlo ARMIENTO 38'), 29.Darryl LACHMAN, 88.Neil KILKENNY (C)
Substitutes not used: 1.Tando VELAPHI (GK), 34.Mason TATAFU
Yellow Cards: Sullivan
Red Cards: None