Glory missed out on the opportunity to climb into the top six as a first-half brace from Matt Derbyshire consigned the men in purple to a 2-0 defeat against Macarthur FC at Campbelltown Stadium.
In what was the first ever A-League meeting between the two sides, the in-form English striker opened the scoring after ten minutes with a close-range finish and then drilled home from the spot after Glory debutant Sebastian Langkamp had been deemed guilty of a trip on Markel Susaeta.
The visitors did threaten to muster a response in the latter stages, but home 'keeper Adam Federici was equal to efforts from both Diego Castro and substitute Carlo Armiento and Head Coach Richard Garcia accepted that over the course of the 90 minutes, his side had not been at their best.
"Certain sections of the game were disappointing," he said.
"We lacked discipline at times and that gave them [Macarthur FC] the openings to get the goals.
"It's about learning from that, improving and making sure that come Wednesday and our next game (away at Sydney FC), we're ready for it.
"To concede just before the half is always hard, because if you're [only] 1-0 down, you've got it all to play for.
"At 2-0 down, we still came out pretty strong and they were on the back foot for a while, but you could tell they were sitting in and protecting their lead.
"It's now about getting the boys back up and approaching Sydney with a different level of enthusiasm and a different level of mentality."
Macarthur were rewarded for their fast start when Benat's searching ball was headed across the face of goal by former Glory man Ivan Franjic and the predatory Derbyshire sent a toe-poke finish into the roof of the net.
Susaeta then came close to doubling the hosts' lead when he flashed a shot across the face of goal having capitalised upon a defensive error and six minutes later, the Spaniard saw another effort parried by Liam Reddy.
Glory's most threatening moment of the opening half-hour, meanwhile, came when Jason Geria delivered a teasing cross from the right and the sliding Castro was just unable to get a meaningful touch before the ball was gratefully gathered by Federici.
With the Bulls continuing to look the more threatening, the first half ended in controversy when Langkamp was adjudged to have impeded Susaeta in the box despite there appearing to be little if any contact and Derbyshire calmly converted the resulting penalty.
Loic Puyo wasted a great opportunity to put the home side all but out of sight two minutes after the restart, blazing a close-range shot wildly over the bar and Glory were grateful to Darryl Lachman on the hour-mark as the Curacao international cleared an Ivan Franjic header off the line.
To their credit, the visitors pressed hard in the final quarter and came close to halving the arrears when Castro latched on to a half-cleared corner and sent in a low shot which took a couple of deflections before Federici managed to claim it.
The Bulls, meanwhile, almost exploited the fact that Glory were throwing numbers forward, Benat twice denied by Reddy in quick succession, before the lively Armiento forced Federici to make a smart stop at the near post with what proved to be the visitors' last chance of the game.
Macarthur FC 2 (Derbyshire 10', 44' (pen)) Perth Glory 0
Campbelltown Stadium, Campbelltown
Referee: Kurt Ams
Macarthur FC: 1.Adam FEDERICI (gk), 4.Benat ETXEBARRIA (21.Jake HOLLMAN 90'), 5.Mark MILLIGAN (C), 6.Aleksandar JOVANOVIC, 7.Ivan FRANJIC (31.Lachlan ROSE 79'), 8.Denis GENREAU, 10.Loic PUYO (29.Antonis MARTIS 70'), 11.Tommy OAR, 15.Aleksandar SUSNJAR, 27.Matt DERBYSHIRE (9.Milislav POPOVIC 89'),33.Markel SUSAETA
Substitutes not used: 3.Antony GOLEC, 12.James MEREDITH, 16. Nick SUMAN (gk)
Yellow Cards: Derbyshire
Red Cards: None
Perth Glory: 33.Liam REDDY (gk), 2.Jason GERIA, 4.Sebastian LANGKAMP (3.Luke BODNAR 74'), 6.Osama MALIK (19.Callum TIMMINS 58'), 8.Kosuke OTA, 9.Bruno FORNAROLI, 17.Diego CASTRO (C), 23.Dane INGHAM (24.Daniel STYNES 74'), 29.Darryl LACHMAN, 38.Ciaran BRAMWELL (20.Carlo ARMIENTO 58'), 88.Neil KILKENNY (15.Brandon WILSON 74')
Substitutes not used: 1.Tando VELAPHI (gk), 22.Josh RAWLINS,
Yellow Cards: Fornaroli
Red Cards: None